import sys
input = sys.stdin.readline

N=int(input())
R=[0]*1000000
B=[0]*1000000

for i in range(N):
    a,b,t=map(int,input().split())

    if a==0:
        R[b-t+300000]+=1
    else:
        B[b-t+300000]+=1

ANS=0
for i in range(len(R)):
    ANS+=R[i]*B[i]

print(ANS)