Replace

#include <bits/stdc++.h>
using namespace std;
string T,P,H;
int main(void){
    cin>>T>>P>>H;
    while(~T.find(P))
        T=T.substr(0,T.find(P))+H+T.substr(T.find(P)+P.size());
    cout<<T<<endl;
    return 0;
}