class Unionfind:
    def __init__(self, size):
        self.root = [x for x in range(size + 1)]
        self.rank = [1] * (size + 1)

    def find(self, x):
        if x != self.root[x]:
            self.root[x] = self.find(self.root[x])

        return self.root[x]

    def union(self, x, y):
        rootx = self.find(x)
        rooty = self.find(y)

        if rootx != rooty:
            if self.rank[rootx] > self.rank[rooty]:
                self.root[rooty] = rootx
            elif self.rank[rootx] < self.rank[rooty]:
                self.root[rootx] = rooty
            else:
                self.root[rooty] = rootx
                self.rank[rootx] += 1

    def connected(self, x, y):
        return self.find(x) == self.find(y)


n = int(input())
a = list(map(int, input().split()))
res = 0
visit = set()

for i in range(n):
    t = a[i]-1
    if t in visit:
        continue

    while not t in visit:
        visit.add(t)
        t = a[t]-1

    res += 1


print(res)