#include <iostream>
#include <string>
#include <algorithm>
#include <vector>
#include <iomanip>
#include <cmath>
#include <stdio.h>
#include <queue>
#include <deque>
#include <cstdio>
#include <set>
#include <map>
#include <bitset>
#include <stack>
#include <cctype>
using namespace std;
int co[200020] = {};
bool bo[200020] = { false };
set<pair<int, int>> st;
int main() {
	long long n, m;
	cin >> n >> m;
	for (int i = 0; i < n; i++) {
		int b, c;
		cin >> b >> c;
		bo[b] = true;
		if (st.find({ b,c }) == st.end()) {
			st.insert({ b,c });
			co[c]++;
		}
	}
	int ans = 0, co1 = 0;
	for (int i = 1; i <= m; i++) {
		if (bo[i]) {
			co1++;
		}
	}
	for (int i = 1; i <= n; i++) {
		if (co[i] != 0) {
			ans += co[i] - 1;
		}
	}
	cout << min(ans,co1 - 1) << endl;
}