from collections import defaultdict

n=int(input())
a=list(map(int,input().split()))
d=defaultdict(int)
for i in a:
    d[i]+=1
cnt_in=0
cnt_out=0
for i in range(1,n+1):
    if d[i]>0:
        cnt_in+=i
    else:
        cnt_out+=i
g=sum(a)
ans=abs(g-(cnt_in+cnt_out))
print(ans)