"""

"""

import sys
from sys import stdin

N = int(stdin.readline())

R = list(map(int,stdin.readline().split()))

for i in range(N-1):
    R[i] -= 1

last = 0
now = 0
ans = 0

while now < N-1:

    nex = 0
    for i in range(last,now+1):
        nex = max(nex , R[i])

    ans += 1
    now = nex
    last = now

print (ans)