N,S,B=map(int,input().split())
H=list(map(int,input().split()))

for i in range(N-1):
    H[i+1]=max(H[i+1],H[i])

for i in range(N-1):
    if H[i+1]-H[i]>S*B:
        print('No')
        exit()

print('Yes')