import std.stdio, std.range, std.random, std.conv, std.string, std.math;
import std.algorithm.comparison, std.algorithm.iteration, std.algorithm.mutation, std.algorithm.searching, std.algorithm.sorting;

void main()
{
    int[] input = readln().strip.split().to!(int[]);
    int N = input[0];
    int K = input[1];

    if((N+1)/2 >= K)
    {
        writeln("YES");
    }else
        writeln("NO");
}