#include <bits/stdc++.h>
using namespace std;

int main() {
  int A, B, O, W;
  cin >> A >> B >> O >> W;
  int infect = 0;
  infect += O;
  if (A > B)
    infect += A;
  else
    infect += B;
  infect += W;
  cout << infect << endl;
  return 0;
}