OI-codes/Luogu/problem/B2051/B2051.cpp

#include <bits/stdc++.h>

using namespace std;

int x, y;

int main() {
    cin >> x >> y;
    cout << (-1 <= x && x <= 1 && -1 <= y && y <= 1 ? "yes" : "no") << endl;
    return 0;
}