from collections import defaultdict
N = int(input())
L = [list(map(int,input().split())) for _ in range(N)]
A,B,T = [list(i) for i in zip(*L)]
dic = defaultdict(int)
for i in range(N):
    if A[i] == 0:
        dic[B[i]+T[i]] += 1
ans = 0
for i in range(N):
    if A[i] == 1:
        ans += dic[B[i]+T[i]]
print(ans)