import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;

/*
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/**
 *
 * @author cteam024
 */
public class Barrels
{
    static String a = "";
    static String list[];
    static int count = 0;
    static int found = 0;
    static char[] digits = new char[3];
    static int k;
    public static void main(String[] args) throws Exception
    {
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
        String[] input = reader.readLine().split(" ");
        k = Integer.parseInt(input[2]);
        digits[0] = input[0].charAt(0);
        digits[1] = input[1].charAt(0);
        digits[2] = input[3].charAt(0);
        int identical = 0;
        if (digits[0] == digits[1]) identical++;
        if (digits[1] == digits[2]) identical++;
        if (digits[0] == digits[2] && identical < 2) identical++;
        identical = 3 - identical;
        System.out.println((powerOf(identical, k - 1) * k) % 1000000007);
        System.exit(0);
    }
    
    static long powerOf(int a, int b)
    {
        if (b < 0)
            return 0;
        if (b == 0)
            return 1;
        long result = a;
        for (int i = 1; i < b; i++)
        {
            result *= a;
            result = result % 1000000007;
        }
        return result;
    }
}