#coding:utf-8

from fractions import Fraction
from math import ceil

a=input()
b=input()
c=float(input())

nml_cost=a//b
nml_cost_rate=nml_cost*Fraction(2,3)
spe_cost=ceil(a/c)

if nml_cost_rate < spe_cost:
	print 'NO'
else:
	print 'YES'