Codeforces-SolutionsA/Codes/1879 A - Rigged!/1879A.cpp

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2023-10-13 20:54:28 +08:00
#include<bits/stdc++.h>
using namespace std;
// Short forms
#define ll long long
#define ull unsigned long long
#define nl '\n'
#define ff first
#define ss second
#define all(x) x.begin(), x.end()
#define sz(x) (int)(x).size()
#define pb push_back
#define mp make_pair
// Loops
#define nlp(i, n) for (int i = 0; i < (int)(n); ++i)
#define lp(i, a, b) for (int i = (int)(a); i < (int)(b); ++i)
#define rlp(i, a, b) for (int i = (int)(a); i > (int)(b); --i)
#define llp(i,a,b) for (ll i= (ll)(a); i < (ll)(ll)(b); ++i)
// STLs
#define pii pair<int, int>
#define vi vector<int>
#define vll vector<ll>
#define vvi vector<vector<int>>
#define vvl vector<vector<ll>>
// Outputs
#define yes cout<<"YES"<<nl
#define no cout<<"NO"<<nl
#define dbg(x) cerr << #x <<" "<< x << endl;
// Constants
#define PI 3.141592653589793238
#define INF LONG_LONG_MAX
#define MOD 1e9+7
// Faster Input Output
#define FAST_IO (ios_base:: sync_with_stdio(false),cin.tie(NULL));
// Maths
ll fact(ll n) { if(n==0) return 1; ll res = 1; for (ll i = 2; i <= n; i++) res = res * i; return res; }
ll nPr(ll n, ll r) { return fact(n) / fact(n - r); }
ll nCr(ll n, ll r) { return fact(n) / (fact(r) * fact(n - r)); }
ll gcd(ll a, ll b) { if (b == 0) return a; return gcd(b, a % b); }
ll lcm(ll a, ll b) { return (a * b) / gcd(a, b);}
ll mypow(ll a, ll b) { ll ans = 1; while(b){ if (b&1) ans = (ans*a) ; b /= 2; a = (a*a); } return ans; }
bool isPrime(ll n) { if(n <= 1) return false; for(ll i = 2; i <= sqrt(n); i++) if(n % i == 0) return false; return true; }
/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
void solve()
{
int n;
cin>>n;
vector<int>str;
vector<int>end;
for(int i=0; i<n; ++i)
{
int x,y;
cin>>x>>y;
str.pb(x);
end.pb(y);
}
for(int i=1; i<n; ++i)
{
if(str[i]>=str[0] && end[i]>=end[0])
{
cout<<-1<<nl;
return;
}
}
cout<<str[0]<<nl;
}
int main()
{
FAST_IO;
int TC = 1;
cin >> TC;
while (TC--) solve();
}