n = int(input())
q = []
for i in range(n):
    b = list(map(int ,input().split()))
    q.append(b)
ans = 0
for i in q:
    if i[0] == 1:
        ans += sum([j[2] for j in q if j[0] == 0 and j[1] < q.index(i)])
print(ans)