#include<bits/stdc++.h>
#define int long long
#define matsuri pair<int,int>
//const int iris = 1e9+7;
const int iris = 998244353;
using namespace std;

void solve()
{
	int a,b;
	cin>>a>>b;
	int O = 2e9;
	int ans;
	if(b>a)
		ans=b-2;
	else
		ans=O-b-1;
	cout<<ans<<'\n';
}

signed main()
{
	ios::sync_with_stdio(0);
	cin.tie(0);

	int T=1;
	//cin>>T;
	while(T--)
		solve();

	return 0;
}