#pragma GCC optimize("Ofast,unroll-loops")
#include <bits/stdc++.h>
using namespace std;

#ifdef WAIMAI
#define debug(HEHE...) cout<<"["<<#HEHE<<"] : ",dout(HEHE)
void dout(){cout<<'\n';}
template<typename T,typename...U>
void dout(T t,U...u){cout<<t<<(sizeof...(u)?", ":""),dout(u...);}
#else
#define debug(...) 7122
#endif

#define int long long
#define ll long long
#define Waimai ios::sync_with_stdio(false),cin.tie(0)
#define FOR(x,a,b) for(int x=a,I=b;x<=I;x++)
#define pb emplace_back
#define F first
#define S second

const int INF = 1e9;
const int SIZE = 2e5 + 5;

int n, m;
vector<int> adj[SIZE], cadj[SIZE];
int a[SIZE], dp[SIZE][2], cdp[SIZE][2];
bool vs[SIZE];

void dfs (int pos, int fa) {
    dp[pos][1] = 1;
    for (int np : adj[pos]) if (np != fa) {
        dfs (np, pos);
        dp[pos][0] += dp[np][1];
        dp[pos][1] += min (dp[np][0], dp[np][1]);
    }
}

void solve() {
    cin >> n >> m;
    FOR (i, 1, n + m) {
        int a, b;
        cin >> a >> b;
        a++, b++;
        if (max (a, b) > n) {
            adj[a].pb (b);
            adj[b].pb (a);
        } else {
            cadj[a].pb (b);
            cadj[b].pb (a);
        }
    }
    FOR (i, 1, n) dfs (i, i);
    for (int i = 1, pos = 1; i <= n; i++) {
        a[i] = pos;
        vs[pos] = 1;
        for (int np : cadj[pos]) if (!vs[np]) {
            pos = np;
            break;
        }
    }

    int ans = INF;
    auto work = [&]() {
        cdp[1][0] = INF, cdp[1][1] = dp[a[1]][1];
        FOR (i, 2, n) {
            cdp[i][0] = dp[a[i]][0], cdp[i][1] = dp[a[i]][1];
            cdp[i][0] += cdp[i - 1][1];
            cdp[i][1] += min (cdp[i - 1][0], cdp[i - 1][1]);
        }
        return min (cdp[n][0], cdp[n][1]);
    };
    ans = min (ans, work());
    reverse (a + 1, a + n + 1);
    ans = min (ans, work());
    cout << ans << '\n';
}

int32_t main() {
    Waimai;
	solve();
}