from itertools import accumulate
N = int(input())
*A, = map(int, input().split())
last = 0
for i, a in enumerate(A):
    if a:
        last = i
A = A[:last+1]

C = list(accumulate([1 if a else 0 for i, a in enumerate(A)][::-1]))[::-1]
C = C[1:]+[0]

if all(a <= (i+1) and (a+c) % (i+1) == 0 for i, (a, c) in enumerate(zip(A, C))):
    print('Yes')
else:
    print('No')