#include<bits/stdc++.h>
using namespace std;
int main() {
    int n,m;
    cin>>n>>m;
    if(n==0) {
        cout<<"no"<<endl; 
    }else if(n%(m+1)==1) {
        cout<<"no"<<endl;  
    } else {
        cout<<"yes"<<endl;
    }
    return 0;
}