#include<iostream>
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<algorithm>
#include<vector>
#include<math.h>
#include<iomanip>
#include<stack>
#include<queue>
#include<set>
#include<map>

using namespace std;
using ll = long long;
using ull = unsigned long long;
using ld = long double;

//const ll mod = 1000000007;
const ll mod = 998244353;
const ld pi = 3.14159265358979;

int main() {
	ios::sync_with_stdio(false);
	cin.tie(0);
	//cout << fixed << setprecision(15);
	int n , m;
	cin >> n >> m;
	map<int , int> mp;
	for(int i = 0; i < n; i++){
		int b , c;
		cin >> b >> c;
		mp[c]++;
	}
	int ans = 0;
	for(auto i : mp){
		if(i.second <= 1)continue;
		ans += (i.second - 1);
	}
	cout << ans << endl;
	return 0;
}