#include <bits/stdc++.h>
#define int long long
using namespace std;
int a,b;
signed main(){
	cin>>a>>b;
	int l=0,r=1e18;
	while(l<=r){
		int mid=(l+r)/2;
		if(a+b<=mid)r=mid-1;
		else l=mid+1;
	}
	cout<<r;
	return 0;
}