#include <bits/stdc++.h> using namespace std;
int main() { string a, b; double k; int cnt; cin >> k >> a >> b; for(int i = 0;i <= a.size() - 1;i++){ if(a[i] == b[i]){ cnt++; } } if(cnt / a.size() * 1.0 >= k){ cout <<"yes"; }else{ cout << "no"; } }
