import std.stdio, std.conv, std.string, std.bigint;
import std.math, std.random, std.datetime;
import std.array, std.range, std.algorithm, std.container, std.format;
string read(){ static string[] ss; while(!ss.length) ss = readln.chomp.split; string res = ss[0]; ss.popFront; return res; }

void main(){
	long n = read.to!long;
	long k = read.to!long;
	
	if(n >= k * 2 - 1) writeln("YES");
	else writeln("NO");
}
