C++ :

#include <iostream>
#include <cstring>
using namespace std;
const int N = 10010;
char ch[N];
int main()
{
    double n ,sum = 0;
    string a , b;
    cin >> n >> a >> b;
    for (int i = 0; i < a.size(); ++i) {
        if(a[i] == b[i]) sum++;
    }
    if(sum/a.size() >= n) cout << "yes";
    else cout << "no";

    return 0;
}