#include <bits/stdc++.h>
#define endl '\n'
using namespace std;

char curr;
int n, k, dp[26];
string s, t, ans;

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);

    freopen("bullcode.in", "r", stdin);
    freopen("bullcode.out", "w", stdout);

    cin>>n>>k>>s>>t;

    memset(dp, -1, sizeof(dp));

    for(int i = 0; i < n; i++)
    {
        if(dp[s[i] - 'a'] != -1)
        {
            ans += (char)(dp[s[i] - 'a'] + 'a');
            continue;
        }

        curr = s[i];
        for(int j = 0; j < k; j++)
        {
            curr = t[curr - 'a'];
        }

        ans += curr;
        dp[s[i] - 'a'] = curr - 'a';
    }

    cout<<ans<<endl;
    return 0;
}