N = int(input())
C = {}
D = {}
for _ in range(N):
    a,b,t = map(int,input().split())
    if a==0:
        C[t-b] = C.get(t-b,0)+1
    else:
        D[t-b] = D.get(t-b,0)+1
ans = 0
for x in C:
    ans += C[x]*D.get(x,0)
print(ans)