#include <stdio.h>
#include <algorithm>
#include <iostream>
#include <string>
#include <vector>
#include <functional>
#include <map>
#include <iomanip>
#include <math.h> 
#include <stack>
#include <queue>
#include <bitset>
#include <cstdlib>
#include <tuple>
#include <cctype>
#include <ctype.h>
#include <set>
#include <sstream>

using namespace std;

int main(){
	int i, j;
	int a, b;

	cin >> a >> b;

	if (a > b) {
		//cout << 2000000000 - a << endl;
		cout << (2000000000 - b) - 1 << endl;
	}
	else {
		//cout << a - 1 << endl;
		cout << b - 2 << endl;
	}
	
















	getchar();
	getchar();
	return 0;
}