#include <bits/stdc++.h>
int main() {
  int k;
  int dim[3] = {0, 0, 0};
  std::cin >> dim[0] >> dim[1] >> dim[2] >> k;
  int parts[3] = {1, 1, 1};
  long long answer = 1;
  int slices = k;
  while (slices > 0) {
    int count = 0;
    for (int j = 0; j < 3; ++j) {
      if (parts[j] < dim[j] && slices > 0) {
        --slices;
        ++count;
        answer /= parts[j];
        answer *= parts[j] + 1;
        ++parts[j];
      }
    }
    if (count == 0) {
      break;
    }
  }
  std::cout << answer;
  return 0;
}
