#include <bits/stdc++.h>

using namespace std;

#define ll long long
#define rep(i, a, n) for (int i = (int)(a); i < (int)(n); i++)
#define rrep(i, n, a) for (int i = (int)(n); i >= (int)(a); i--)

void solve(){
    int n,m; cin >> n >> m;
    vector<vector<int>> adj(2*n);
    rep(i,0,m){
        int x,y; cin >> x >> y;
        x--;y--;
        adj[x].push_back(y);
        adj[y].push_back(x);
    }
    vector<int> color(2*n);
    iota(color.begin(), color.end(), 1);
    vector<bool> seen(n*2, false);
    stack<int> todo;
    rep(i,0,2*n) todo.push(i);
    while(!todo.empty()){
        int x = todo.top();
        todo.pop();
        if(seen[x]) continue;
        seen[x] = true;
        for(int u: adj[x]){
            color[u] = color[x];
            todo.push(u);
        }
    }

    int ans = 0;
    sort(color.begin(), color.end());
    int s = 1;
    rep(i,1,2*n){
        if(color[i] != color[i-1]){
            ans += s % 2;
            s = 1;
        } else s++;
    }
    ans += s % 2;
    cout << ans/2;
}

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    solve();

    return 0;
}