#include<iostream>
#include<algorithm>
#include<string.h>
#include<vector>
using namespace std;
// #define debug(x) cout<<"[debug]"#x<<"="<<x<<endl
typedef long long ll;
typedef long double ld;
typedef pair<int,int> pii;
const ld eps=1e-8;
const int INF=0x3f3f3f3f,mod=998244353;


int main()
{
    string s;
    string t;
    int n;
    cin>>s>>t>>n;
    string res=s;
    while(n--)
    {
        res+='_';
        res+=t;
    }
    cout<<res<<endl;
}