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

int main() {
    int a, b, c, k;
    std::cin >> a;
    std::cin >> b;
    std::cin >> k;
    std::cin >> c;
    int x = pow(2, k);
    x = x * k;
    x = x / 2;
    unsigned long long f = (unsigned long long) x % (unsigned long long) 1000000007;
    std::cout << f << std::endl;
    return 0;
}