import sys
readline = sys.stdin.readline
from collections import *

N = int(readline())
A = []
D = defaultdict(int)
for i in range(N):
    a, b, t, = map(int,readline().split())
    if a:
        A.append(b - t)
    else:
        D[b - t] += 1
        
ans = 0
for a in A:
    ans += D[a]
print(ans)