3346. 皇后问题

n = int(input())
row = [0]*(n+1)
col = [0]*(n+1)
slash1 = [0]*(2*n)
slash2 = [0]*(2*n)
for _ in range(n):
    x, y = map(int, input().split())
    row[x] += 1
    col[y] += 1
    slash1[x-y+(n-1)] += 1
    slash2[x+y-(n-1)] += 1
res = 0
for i in range(1, n+1):
    res += (row[i]*(row[i]-1))//2
    res += (col[i]*(col[i]-1))//2
for i in range(1, 2*n):
    res += (slash1[i]*(slash1[i]-1))//2
    res += (slash2[i]*(slash2[i]-1))//2
print(res)