from collections import defaultdict


def main():
    n = int(input())

    red = defaultdict(int)
    blue = defaultdict(int)
    for _ in range(n):
        a, b, t = map(int, input().split())
        if a == 0:
            red[b - t] += 1
        else:
            blue[b - t] += 1

    ans = sum([red[x] * blue[x] for x in set(red) & set(blue)])
    print(ans)


if __name__ == "__main__":
    main()