#include <bits/stdc++.h>
using namespace std;

int main()
{
#ifndef ONLINE_JUDGE
    freopen ("hangkien.out", "r", stdin);
    freopen ("hangkien.inp", "w", stdout);
#endif
    string s,t,t1 = "";
    long long a,b,n,i;
    cin >> a >> b >> s >> t >> n;
    reverse(s.begin(),s.end());
    if (a + b - n < 2)
    {
        cout << t << s;
        return 0;
    }
    for (i = 1 ; i <= b ; i++)
    {
        s = '*' + s + '*';
    }
    for (i = 1 ; i <= b + a ; i++)
    {
        t1 += '*';
    }
    t = t1.substr(0,a+b-n) + t + t1;
    for (i = 0 ; i < t.size() ; i++)
    {
        if(t[i] != '*')
        {
            cout << t[i];
        }
        if(i < s.size())
        if(s[i] != '*')
        {
            cout << s[i];
        }
    }
    return 0;
}