#pragma GCC optimize ("O3")
#pragma GCC optimize ("unroll-loops")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
#include <bits/stdc++.h>
typedef long long ll;
typedef long double ld;
using namespace std;
const int N = 2e5 + 5;
int n, m;
int memo1[N][2];
int memo2[N][2][2];
vector<int> g[N];
int solve2(int node, int par, bool need) {
	int &ans = memo1[node][need];
	if(~ans)
		return ans;
	if(need) {
		ans = 1;
		for(auto i : g[node]) {
			if(i == par)
				continue;
			ans += solve2(i, node, 0);
		}
	} else {
		int op1 = 1;
		int op2 = 0;
		for(auto i : g[node]) {
			if(i == par)
				continue;
			op1 += solve2(i, node, 0);
			op2 += solve2(i, node, 1);
		}
		ans = min(op1, op2);
	}
	return ans;
}
int solve(int i, bool need, bool first) {
	if(i == n)
		return (need && !first) ? 1e9 : 0;
	int &ans = memo2[i][need][first];
	if(~ans)
		return ans;
	if(need)
		ans = solve(i + 1, 0, !i ? 1 : first) + solve2(i, i, 1);
	else {
		ans = solve(i + 1, 1, !i ? 0 : first) + solve2(i, i, 0);
		ans = min(ans, solve(i + 1, 0, !i ? 1 : first) + solve2(i, i, 1));
	}
	return ans;
}
int main() {
    ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
    cin >> n >> m;
    for(int i = 0;i < n + m;i++) {
		int u, v;
		cin >> u >> v;
		if(u >= n || v >= n) {
			g[u].push_back(v);
			g[v].push_back(u);
		}
	}
	memset(memo1, -1, sizeof memo1);
	memset(memo2, -1, sizeof memo2);
	cout << min(solve(0, 0, 0), solve(0, 1, 1)); 
    return 0;
}