#include <iostream>
#include <vector>
#include <math.h>
#include <iomanip>

using namespace std;
double numOfC(int k, int a, int b)
{

    double result = 0;
    long long result2 = 0;
    //double pocetCisel = ;
    for(int i = 0;i < k;i++)
    {
        result += (pow(2,k)/2);
    }

    double neco = (int)(result/1000000007);
    result -= neco*1000000007;

    //result % 1000000007;


    if(a==b)
    {
        return 2 * result;
    }
    return result;
}

int main()
{
    int a,b,c,k;

    cin >> a;
    cin >> b;
    cin >> k;
    cin >> c;

    cout << dec << fixed << setprecision(0) << numOfC(k,a,b);
    return 0;
}