N,M = map(int,input().split())

color = [set() for _ in range(N+1)]
for i in range(N):
    b,c = map(int,input().split())
    color[c].add(b)

ans = 0
for i in range(1,N+1):
    if color[i]:
        ans += len(color[i]) - 1
print(ans)