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

int main(){
  int x1, y1, x2, y2;
  cin >> x1 >> y1;
  cin >> x2 >> y2;

  if(x1 == y1 && x2 == y2 && x1 > x2)
    cout << x1 + 1 << endl;
  else
    cout << max(x1, y1) << endl;
}