#include <bits/stdc++.h>
using namespace std;
typedef unsigned long long ul;
typedef signed long long ll;
ul over = 1000000007;

int main(void)
{
  cin.tie(0);
  ios::sync_with_stdio(false);
  cout << fixed;
  ll x, y, x2, y2;
  cin >> x >> y >> x2 >> y2;
  ll ans = max(x, y);
  if (x==y && x2==y2 && x2 < y2) {
    ans++;
  }
  cout << ans << endl;
  return 0;
}