#include <bits/stdc++.h>
#define rep(i,n) for(int i=0;i<(int)(n);i++)
using namespace std;
using ll = long long ;
using P = pair<int,int> ;
using pll = pair<long long,long long>;
constexpr int INF = 1e9;
constexpr long long LINF = 1e17;
constexpr int MOD = 1000000007;
constexpr double PI = 3.14159265358979323846;
ll mx = 2*INF;

int main(){
    ll a ,b;
    cin >> a >> b;
    if(a>b){
        cout << mx-b-1 << endl;
    }else{
        cout << b-1-1 << endl;
    }
    return 0;
}