#include <bits/stdc++.h>

using namespace std;

struct Initializer {
  Initializer() {
    cin.tie(0);
    ios::sync_with_stdio(0);
    cout << fixed << setprecision(15);
  }
} initializer;

int main() {
  int a, b;
  cin >> a >> b;
  cout << (a < b ? b - 2 : 1999999999 - b) << endl;
}