#include<stdio.h>
int main()
{
    int x,y;
    scanf("%d %d",&x,&y);
    if(x>=-1&&x<=1&&y>=-1&&y<=1)
    printf("yes");
    else
    printf("no");
    return 0;
}

#include<iostream>
using namespace std;
int main()
{
    int x,y;
    cin>>x>>y;
    if((x >= -1 && x <= 1) && (y >= -1 && y <= 1)){
        cout<<"yes"<<endl;
    }else cout<<"no"<<endl;
    return 0;
}