#include <bits/stdc++.h>
using namespace std;
#define sorted(a) sort(a.begin(), a.end());
typedef long long ll;
const long mod = 1e9 + 7;

int main(void) {
#ifdef DEBUG
  freopen("input.txt", "r", stdin);
#endif

  ios_base::sync_with_stdio(false);
  cin.tie(NULL);

  int X, Y, X2, Y2;
  cin >> X >> Y;
  cin >> X2 >> Y2;

  if (X == Y && X2 == Y2 && X > X2)
    cout << X + 1 << endl;
  else
    cout << max(X, Y) << endl;
  return 0;
}