#include <iostream>
#include <cstdio>
#include <vector>
#include <cmath>
#include <algorithm>
#include <ctime>
#include <string>


#define y1 y11
#define pi acos(-a)
#define eps (double)(1e-9)
#define pb push_back

using namespace std;


int col = 0;
vector<int> g[250];
bool used[250];
int d[250][250];
int color[250];
int deg[250];
int c[250];

void dfs(int u, int col)
{
    used[u] = true;
    color[u] = col;
    for (int i = 0; i < g[u].size(); i++)
    {
        int v = g[u][i];
        if (!used[v])
            dfs(v, col);
    }
}

int main()
{
    //freopen("domino.in", "r", stdin);
    //freopen("domino.out", "w", stdout);
    int n, m;
    cin >> m >> n;
    for(int i = 0; i < m + 1; i++)
    {
        for (int j = 0; j < m + 1; j++)
            if (i != j)
                d[i][j] = 1;
        deg[i] = m + 1;
    }
    for(int i = 0; i < n; i++)
    {
        int a, b;
        cin >> a >> b;
        if (a != b){
            d[a][b] = 0;
            d[b][a] = 0;
            deg[a]--;
            deg[b]--;
        }
        if (a == b){
            d[a][a] = 0;
            deg[a]--;
        }
    }
    for(int i = 0; i < m + 1; i++)
        for (int j = 0; j < m + 1; j++)
            if(d[i][j] == 1)
                g[i].pb(j);
    for (int i = 0; i < (m+1); i++){
        if (!used[i])
        {
            dfs(i, col);
            col++;
        }
    }
    for (int i = 0; i < m + 1; i++){
        c[color[i]] += deg[i] % 2;
    }
    int ans = 0;
    for (int i = 0; i < col; i++){
        if (c[i] > 0)
            ans += c[i] / 2;
        else
            ans++;
    }
    cout << ans;
    return 0;
}