#define _GLIBCXX_DEBUG
#include <bits/stdc++.h>
#include <atcoder/dsu>
using namespace atcoder;
using namespace std;
typedef long long ll;
#define rep(i,a,b) for(int i=a;i<b;i++)
using vi = vector<int>; 
using vvi = vector<vi>; 
using li =vector<ll>;
using lli=vector<li>;
using si =vector<char>;
using ssi =vector<si>;
struct Edge {
  int to, cost;
  Edge(int to, int cost) : to(to), cost(cost) {}
};
//using mint = modint998244353;
const long long INF = 1e18;
const long long MOD=1e9+7;
//bit全探索 rep(i,0,1<<(n-1)){rep(j,0,n-1)if(I&(1<<j))}
//int a = s[0] - ‘0’;文字列から数字
//int a=atoi(s.c_str());
//“ABCDEFGHIJKLMNOPQRSTUVWXYZ"
//printf("%.9f\n", ans);
//printf("%.20llf\n",solve(N));
int main() { ll x,y;cin>>x>>y;
ll a,b;cin>>a>>b;
if(a==b&&x==y)cout<<x+1;
else if(x==y)cout<<x;
else cout<<max(x,y);

}