diff --git a/Codes/1980 C - Sofia and the Lost Operations/1980C.cpp b/Codes/1980 C - Sofia and the Lost Operations/1980C.cpp
new file mode 100644
index 0000000..753bbcd
--- /dev/null
+++ b/Codes/1980 C - Sofia and the Lost Operations/1980C.cpp	
@@ -0,0 +1,46 @@
+#include <bits/stdc++.h>
+using namespace std;
+#define ll long long
+#define endl '\n'
+ll pow(ll x,ll y,ll m=1e9+7){ll ans=1;x%=m;while(y){if(y&1)ans=(ans*x)%m;x=(x*x)%m;y>>=1;}return ans;}
+
+void solve()
+{
+    int n,m;
+    cin>>n;
+    vector<int>a(n),b(n);
+    for(auto &i:a)  cin>>i;
+    for(auto &i:b)  cin>>i;
+    cin>>m;
+    vector<int>d(m);
+    map<int,int>mp;
+    for(int i=0; i<m; ++i)
+    {
+        cin>>d[i];
+        mp[d[i]]++;
+    }   
+    bool f=1;
+    for(int i=0; i<n; ++i)
+    {
+        if(a[i]==b[i]) continue;
+        if(mp[b[i]])
+            mp[b[i]]--;
+        else
+            f=0;
+    }
+    if(count(b.begin(),b.end(), d[m-1])==0) f=0;
+    if(f)   cout<<"YES\n";
+    else cout<<"NO\n";
+}
+
+signed main()
+{
+    ios_base::sync_with_stdio(false), cin.tie(nullptr);
+    int TCS = 1;
+    cin >> TCS;
+    for (int TC = 1; TC <= TCS; ++TC)
+    {
+        // cout<<"Case "<<TC<<": ";
+        solve();
+    }
+}
\ No newline at end of file
diff --git a/Codes/1980 D - GCD-sequence/1980D.cpp b/Codes/1980 D - GCD-sequence/1980D.cpp
new file mode 100644
index 0000000..420901b
--- /dev/null
+++ b/Codes/1980 D - GCD-sequence/1980D.cpp	
@@ -0,0 +1,61 @@
+#include <bits/stdc++.h>
+using namespace std;
+#define ll long long
+#define endl '\n'
+ll pow(ll x,ll y,ll m=1e9+7){ll ans=1;x%=m;while(y){if(y&1)ans=(ans*x)%m;x=(x*x)%m;y>>=1;}return ans;}
+
+bool good(vector<int>v, int del)
+{
+    v.erase(v.begin()+del);
+    int last=gcd(v[0],v[1]);
+    for(int i=1; i<v.size()-1; ++i)
+    {
+        int cur=gcd(v[i],v[i+1]);
+        if(cur<last)
+        {
+            del=i;
+            return false;
+        }
+        last=cur;
+    }
+    return true;
+}
+
+void solve()
+{
+    int n;
+    cin>>n;
+    vector<int>v(n);
+    for(auto &i:v)  cin>>i;
+    int del=-1;
+    int last=gcd(v[0],v[1]);
+    for(int i=1; i<n-1; ++i)
+    {
+        int cur=gcd(v[i],v[i+1]);
+        if(cur<last)
+        {
+            del=i;
+            break;
+        }
+        last=cur;
+    }
+    if(del==-1)
+    {
+        cout<<"YES\n";
+        return;
+    }
+    if(good(v,del-1) || good(v,del) || good(v,del+1)) cout<<"YES\n";
+    else    cout<<"NO\n";
+}
+
+signed main()
+{
+    ios_base::sync_with_stdio(false), cin.tie(nullptr);
+    int TCS = 1;
+    cin >> TCS;
+    for (int TC = 1; TC <= TCS; ++TC)
+    {
+        // cout<<"Case "<<TC<<": ";
+        solve();
+    }
+}
\ No newline at end of file
diff --git a/Readme.md b/Readme.md
index 7b92b55..3260e3f 100644
--- a/Readme.md
+++ b/Readme.md
@@ -331,9 +331,11 @@ This repository contains my solutions of Codeforces problems. They are in C++ la
 | 319 | 1977 A | Little Nikita | [Question](https://codeforces.com/problemset/problem/1977/A) | [Solution](https://github.com/ShazidMashrafi/Codeforces-Solutions/tree/master/Codes/1977%20A%20-%20Little%20Nikita)
 | 320 | 1980 A | Problem Generator | [Question](https://codeforces.com/problemset/problem/1980/A) | [Solution](https://github.com/ShazidMashrafi/Codeforces-Solutions/tree/master/Codes/1980%20A%20-%20Problem%20Generator)
 | 321 | 1980 B | Choosing Cubes | [Question](https://codeforces.com/problemset/problem/1980/B) | [Solution](https://github.com/ShazidMashrafi/Codeforces-Solutions/tree/master/Codes/1980%20B%20-%20Choosing%20Cubes)
-| 322 | 1981 A | Turtle and Piggy Are Playing a Game | [Question](https://codeforces.com/problemset/problem/1981/A) | [Solution](https://github.com/ShazidMashrafi/Codeforces-Solutions/tree/master/Codes/1981%20A%20-%20Turtle%20and%20Piggy%20Are%20Playing%20a%20Game)
-| 323 | 1981 B | Turtle and an Infinite Sequence | [Question](https://codeforces.com/problemset/problem/1981/B) | [Solution](https://github.com/ShazidMashrafi/Codeforces-Solutions/tree/master/Codes/1981%20B%20-%20Turtle%20and%20an%20Infinite%20Sequence)
-| 324 | 1981 C | Turtle and an Incomplete Sequence | [Question](https://codeforces.com/problemset/problem/1981/C) | [Solution](https://github.com/ShazidMashrafi/Codeforces-Solutions/tree/master/Codes/1981%20C%20-%20Turtle%20and%20an%20Incomplete%20Sequence)
+| 322 | 1980 C | Sofia and the Lost Operations | [Question](https://codeforces.com/problemset/problem/1980/C) | [Solution](https://github.com/ShazidMashrafi/Codeforces-Solutions/tree/master/Codes/1980%20C%20-%20Sofia%20and%20the%20Lost%20Operations)
+| 323 | 1980 D | GCD-sequence | [Question](https://codeforces.com/problemset/problem/1980/D) | [Solution](https://github.com/ShazidMashrafi/Codeforces-Solutions/tree/master/Codes/1980%20D%20-%20GCD-sequence)
+| 324 | 1981 A | Turtle and Piggy Are Playing a Game | [Question](https://codeforces.com/problemset/problem/1981/A) | [Solution](https://github.com/ShazidMashrafi/Codeforces-Solutions/tree/master/Codes/1981%20A%20-%20Turtle%20and%20Piggy%20Are%20Playing%20a%20Game)
+| 325 | 1981 B | Turtle and an Infinite Sequence | [Question](https://codeforces.com/problemset/problem/1981/B) | [Solution](https://github.com/ShazidMashrafi/Codeforces-Solutions/tree/master/Codes/1981%20B%20-%20Turtle%20and%20an%20Infinite%20Sequence)
+| 326 | 1981 C | Turtle and an Incomplete Sequence | [Question](https://codeforces.com/problemset/problem/1981/C) | [Solution](https://github.com/ShazidMashrafi/Codeforces-Solutions/tree/master/Codes/1981%20C%20-%20Turtle%20and%20an%20Incomplete%20Sequence)