from math import sqrt,sin,cos,tan,ceil,radians,floor,gcd,exp,log,log10,log2,factorial,fsum
from heapq import heapify, heappop, heappush
from bisect import bisect_left, bisect_right
from copy import deepcopy
import copy
import random
from random import randrange
from collections import deque,Counter,defaultdict
from itertools import permutations,combinations
from decimal import Decimal,ROUND_HALF_UP
#tmp = Decimal(mid).quantize(Decimal('0'), rounding=ROUND_HALF_UP)
from functools import lru_cache, reduce
#@lru_cache(maxsize=None)
from operator import add,sub,mul,xor,and_,or_,itemgetter
import sys
input = sys.stdin.readline
# .rstrip()
INF = 10**18
mod1 = 10**9+7
mod2 = 998244353

#DecimalならPython
#再帰ならPython!!!!!!!!!!!!!!!!!!!!!!!!!!


'''



'''

N = int(input())
P = list(map(int, input().split()))

G = [0]*(N+1)
for i in range(N):
    G[P[i]] = i+1

ans = 0
for i in range(N):
    nx = P[i]
    
    if nx == i+1:
        pass
    else:
        ans += 1
        P[G[i+1]-1] = nx
        G[nx] = G[i+1]
        P[i] = i+1

print(ans)