E. Interval Sweep.cpp

//E. Interval Sweep
#include <iostream>
using namespace std;

int main ()
{
    int a, b;

    cin >> a >> b;
    if (a==0 && b==0)
        cout <<"NO";
    else if( a==b || a==b+1 || b==a+1 )
        cout << "YES";
    else
        cout << "NO";

    return 0;
}