#!/usr/bin/env python3

def main():
    N = int(input())
    R = list(map(lambda i: int(i) - 1, input().split())) + [N - 1]
    now = 0
    next = R[0]
    ans = 0
    while now < N - 1:
        checked = now
        now = next
        temp = 0
        for i in range(checked + 1, R[next] + 1):
            if R[i] >= temp:
                next = i
        ans += 1
    print(ans)



if __name__ == '__main__':
    main()