from collections import defaultdict as dd

n = int(input())
X = dd(int)
Y = dd(int)
for _ in range(n):
    a, b, t = map(int, input().split())
    if a == 0:
        X[b - t] += 1
    else:
        Y[b - t] += 1
ans = 0
for k, v in X.items():
    ans += v * Y[k]
print(ans)