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

int main() {
    using namespace std;
    int a,b,c,k;
    cin >> a >> b >> k >> c;

    if(c != a && c != b) {
        cout << 0 << endl;
        return 0;
    }

    long long result = 1;
    long long maxMult = pow(2, 5);

    int i = k;
    int alpha = 0;
    long long currentMult;

    while(i >= 1) {

        if(i >= 5) {
            alpha = 5;
            currentMult = maxMult;
        } else {
            alpha = i;
            currentMult = pow(2, alpha);
        }

        result *= currentMult;
        result = result % 1000000007;

        i -= alpha;
    }

    cout << (((result * (long long)(k)) / 2L) % 1000000007L) << endl;

    return 0;
}