#include <iostream>
#include <vector>
#include <string>
#include <algorithm>
#include <math.h>
using namespace std;

int main() {
    int a,b;
    cin >> a >> b;
    if(a > b)cout << 2000000000-b-1 << endl;
    if(a < b)cout << b-2 << endl;
    return 0;
}