#include <iostream>

using namespace std;

int main(int argc, const char* argv[])
{
	int A, B;
	cin >> A >> B;
	int cnt;
	if (A < B)
		cnt = B - 1 - 1;
	else
		cnt = 2000000000 - (B - 1) - 1 - 1;
	cout << cnt << endl;
	return 0;
}