#include <cstdio>
#include <cstring>
#include <cstdlib>
#include <vector>
#include <queue>
#include <string>
#include <functional>
#include <iostream>


using namespace std;
 
//namaega184 
 
int main(){
	
	int x,y,x1,y1;scanf("%d%d%d%d",&x,&y,&x1,&y1);
	int ans=max(x,y);if(x==y&&x1==y1)ans++;
	printf("%d\n",ans);  
	return 0; 
}