#include<bits/stdc++.h>
using namespace std;
int main(){
	string a,s;
	int n,i,j;
	cin>>a>>s;
	cin>>n;
	for(j=0;j<n;j++){
		cout<<s[j];
	}
	for(int i=0;i<a.size();i++){
		cout<<a[i];
	}
	for(;j<s.size();j++){
		cout<<s[j];
	}
	return 0;
}

/**************************************************************
	Problem: 2020
	User: zzz
	Language: C++
	Result: Accepted
	Time:14 ms
	Memory:2076 kb
****************************************************************/