a=int(input())
b=[]
for i in range(0,a):
    c,d,e=map(int,input().split())
    c=c+d+e
    b.append(c)
c=0
for i in range(0,a-2):
    for j in range(i+1,a+1):
        if (b[i]+10>=b[j])or(b[i]-10<=b[j]):
            c+=1
print(c)