//Normal

#define _GLIBCXX_DEBUG
#define ll long long
#include <bits/stdc++.h>
using namespace std;
using Graph = vector<vector<int>>;

void print(auto a){
  cout << a;
}

void prints(auto a){
  cout << a << " ";
}

void prints(){
  cout << " ";
}

void printl(auto a){
  cout << a << endl;
}

void printl(){
  cout << endl;
}

void fix(int n){
  cout << fixed << setprecision(n);
}

int main(){
  int X, Y, X1, Y1; cin >> X >> Y >> X1 >> Y1;

  bool flag = false;
  if(X == Y and X1 == Y1 and X1 < X) flag = true;

  flag ? printl(max(X, Y) + 1) : printl(max(X, Y));

  return 0;
}