import sys
input = sys.stdin.buffer.readline
from collections import defaultdict 


def main():
    N = int(input())
    dicx = defaultdict(int)
    dicy = defaultdict(int)
    for _ in range(N):
        a,b,t = map(int,input().split())
        v = t - b
        if a == 0:
            dicx[v] += 1
        else:
            dicy[v] += 1
    ans = 0
    for z in dicx:
        ans += dicx[z]*dicy[z]
    print(ans)

if __name__ == '__main__':
    main()