n=int(input())
genre=[]
answer= 0
counter=0

for k in range(n):
    genre.append(int(input()))

position = [0 for i in range(max(genre)+1)]

for k in range(n) :
    if not position[genre[k]]:
        position[genre[k]] = 1
        counter = 0
        for v in range(k+1,n) :
            if not position[genre[v]]:
                counter+= 1
            elif genre[k]==genre[v]:
                answer+=counter
print(answer)