#include <iostream>
#include <cstdio>

using namespace std;

const int longest = 2000000000;

int main() {
	int a, b, ans;

	cin >> a >> b;
	if (a == b) {
		ans = 0;
	} else if (a > b) {
		ans = longest - b - 1;
	} else {
		ans = b - 1 - 1;
	}
	cout << ans << endl;
	return 0;
}