n,s,b=map(int,input().split())
h=list(map(int,input().split()))
k=[h[0]]
for i in range(n-1):
  if k[-1]<h[i+1]:
    k.append(h[i+1])
for i in range(len(k)-1):
  if s*b>=(k[i+1]-k[i]):
    pass
  else:
    print("No")
    exit()
print("Yes")