#include <bits/stdc++.h>
    #define ll long long
    #define pb 	push_back
    using namespace std;
    int main(){
    int n ; cin >> n; 
    char a[n];
    for(int i = 0 ; i < n ; i++) cin >> a[i] ;
    int b ; char c; 
    cin >> b >> c;
    a[b-1] = c;
    for(auto x : a) cout << x ;

}