#include <iostream>
#include <string>
#include <algorithm>
#include <utility>
#include <cmath>
#include <cstdlib>
#include <map>
#include <set>
#include <queue>
#include <vector>
using namespace std;
#define MOD 1000000007

long long modpow(long long a, long long n, long long mod) {
    long long res = 1;
    while (n > 0) {
        if (n & 1) res = res * a % mod;
        a = a * a % mod;
        n >>= 1;
    }
    return res;
}

int main() {
    long long A, B, C, K; cin >> A >> B >> C >> K;
    cout << ((A * B % MOD) * C % MOD) * modpow(2, K, MOD) % MOD;
}