#include <bits/stdc++.h>
using namespace std;
using ll=long long;
using ld=double;
using vll=vector<ll>;
#define FOR(i,a,b) for(ll i=a;i<(ll)b;++i)
#define ROF(i,a,b) for(ll i=a;i>=(ll)b;--i)
#define PB push_back

#define M 1'000'000'007

int main(){
  ios::sync_with_stdio(0);cin.tie(0);

  int64_t A, B, K, C;
  cin >> A >> B >> K >> C;

  int64_t m = 1;
  for(int64_t i = 0; i < K-1; i++){
    m = (m*2)%M;
  }
  m = (m*K)%M;
  cout << m << endl;

  return 0;
}