N = int(input())
R = list(map(int,input().split()))
cnt = 1
now = 0
next = 0
for i in range(N-1):
    if i <= now:
        next = max(next,R[i]-1)
    else:
        cnt += 1
        now = next
        next = max(next,R[i]-1)
    if next == N -1:
        break
print(cnt)