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

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

t = []
for g in G:
    t.append(len(g))

res = 0
for tt in t:
    if tt > 0:
        res += tt-1

print(res)