x,y=map(int,input().split())
n=int(input())
a=list(map(int,input().split()))+[1e6]
b=x/3.6
c=y/3.6
v='YES'
for i in range(n):
  d=a[i]/b*c
  if a[i+1]<d:
    v='NG'
    break
print(v)