#include<bits/stdc++.h>
#define rep(i,a,n) for (int i = a;i < n;i++)
using namespace std;

int main() {
    int a,b; cin >> a >> b;
    if(a > b){
        cout << 2000000000-b-1 << endl;
    }else{
        cout << b-2 << endl;
    }
}