#include <bits/stdc++.h> using namespace std; using ll = long long; using P = pair<int,int>; #define rep(i,n) for(int i=0;i<n;i++) const ll mod = ll(1e9) + 7; const int INF = 1<<29; int main(){ int a,b; cin >> a >> b; int ans = 0; if (a>b) ans += ll(2*1e9)-b-1; else ans += b - 2; cout << ans << endl; return 0; }