#include <iostream>
#include <cstdio>
#include <cmath>
#include <cstdio>
#include <cstring>
#include <string>
#include <vector>
#include <set>
#include <map>
#include <stack>
#include <queue>
#include <deque>
#include <algorithm>

#define CK(N,A,B) (A<=N&&N<B)
#define REP(i,a,b) for(int i=a;i<b;i++)
#define RREP(i,a,b) for(int i=(b-1);a<=i;i--)
#define F first
#define S second
#define ll long long

const int INF = 1e9;
const long long  LLINF = 1e18;

using namespace std;

int x,y,tx,ty;

int main(){
  cin>>x>>y>>tx>>ty;
  if(x==y && tx==ty && (tx<x&&ty<y)){
    cout<<x+1<<endl;
  }else{
    cout<<max(x,y)<<endl;
  }
  return 0;
}