#jenga
N=int(input())
a=[int(i) for i in input().split()]
t=N
i=N-1
c=0
#rint (a)
while i>=0 and t>0:
    while i>=0 and a[i]!=t:
   #     print (i)
        i-=1
    if i>=0 and a[i]==t:
        c+=1
 #       print (i)
     #   print (t)
        i-=1
    t-=1
print (N-c)