#include <cstdio>
#include <algorithm>
using namespace std;

int main(void) {
  int x, y, x2, y2;
  scanf("%d%d%d%d", &x, &y, &x2, &y2);
  int res = max(x, y);
  if(x==y && x2==y2 && x>x2) { res++; }
  printf("%d\n", res);
  return 0;
}