import sys

sys.setrecursionlimit(200005)
int1 = lambda x: int(x)-1
p2D = lambda x: print(*x, sep="\n")
def II(): return int(sys.stdin.readline())
def LI(): return list(map(int, sys.stdin.readline().split()))
def LI1(): return list(map(int1, sys.stdin.readline().split()))
def LLI(rows_number): return [LI() for _ in range(rows_number)]
def LLI1(rows_number): return [LI1() for _ in range(rows_number)]
def SI(): return sys.stdin.readline().rstrip()
# dij = [(0, 1), (-1, 0), (0, -1), (1, 0)]
dij = [(0, 1), (-1, 0), (0, -1), (1, 0), (1, 1), (1, -1), (-1, 1), (-1, -1)]
inf = 10**16
md = 998244353
# md = 10**9+7

n = II()
aa = LI1()
atoi = {a: i for i, a in enumerate(aa)}
cnt = 0

for i in range(n):
    while aa[i] != i:
        a = aa[i]
        a1 = aa[i]-1
        j = atoi[a1]
        aa[i] = a1
        aa[j] = a
        atoi[a1] = i
        atoi[a] = j
        cnt += 1
        # print(aa)

print(cnt)