n, m = map(int, input().split())

memo = [set() for _ in range(n)]

for _ in range(n):
    b, c = map(int, input().split())
    b, c = b - 1, c - 1
    memo[c].add(b)

ans = 0
for i in range(n):
    temp = len(list(memo[i]))
    ans += max(0, temp - 1)
print(ans)