using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

class Program
{
    static void Main(string[] args)
    {
        string S, T;
        S = Console.ReadLine();
        T = Console.ReadLine();
        int N;
        N = int.Parse(Console.ReadLine());
        string ans = S;
        for(int i=0; i<N; ++i)
        {
            ans += "_" + T;
        }
        Console.WriteLine(ans);
    }
}