#include <bits/stdc++.h>

using namespace std;

struct UnionFind{
    vector<int> par;
    vector<int> edg;

    UnionFind(int N) : par(N), edg(N){
        for(int i = 0; i < N; ++i){
            par[i] = -1;
            edg[i] = 0;
        }
    }

    int root(int x){
        if(par[x] < 0) return x;
        return par[x] = root(par[x]);
    }

    void unite(int x, int y){
        int rx = root(x);
        int ry = root(y);
        if(rx == ry){
            edg[rx]++;
            return;
        }
        par[ry] = par[rx] + par[ry];
        par[rx] = ry;
        edg[ry] += edg[rx] + 1;
    }

    bool same(int x, int y){
        int rx = root(x);
        int ry = root(y);
        return rx == ry;
    }

    long long size(int x){
        return -par[root(x)];
    }

    long long edge(int x){
        return edg[root(x)];
    }
};

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

    int n, m; cin >> n >> m;
    assert(1 <= n <= 100000);
    assert(0 <= m <= 100000);

    UnionFind uf(2 * n);
    for(int i = 0; i < m; i++){
        int a, b; cin >> a >> b;
        assert(1 <= a <= 2 * n);
        assert(1 <= b <= 2 * n);
        a--, b--;
        uf.unite(a, b);
    }
    
    int ans = 0;
    for(int i = 0; i < 2 * n; i++){
        if(uf.root(i) == i && uf.size(i) % 2) ans++;
    }
    cout << ans / 2 << endl;
}