16 lines
265 B
C++
16 lines
265 B
C++
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#include<bits/stdc++.h>
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using namespace std;
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int main()
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{
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long long n;
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int count=0;
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cin>>n;
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while(n!=0)
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{
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if(n%10==4 || n%10==7) count++;
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n=n/10;
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}
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if(count==4 || count==7) cout<<"YES"<<endl;
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else cout<<"NO"<<endl;
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}
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