#include <cstdio>
const int MAXN = 100010;
int n, m, x, y, s, t;
int f[MAXN], c[MAXN], d[MAXN], o[MAXN];
int find(int x) {
    return f[x] == x ? x : f[x] = find(f[x]);
}
int main() {
    freopen("sent.in","r",stdin);
    freopen("sent.out","w",stdout);
    scanf("%d%d", &n, &m);
    for(int i=1; i<=n; i++)
        f[i] = i;
    for(int i=1; i<=m; i++) {
        scanf("%d %d", &x, &y);
        if(x == y) continue;
        s = find(x), t = find(y);
        if(s != t) {
            f[s] = y; // or f[t] = x;
            c[x]++, c[y]++;
        }
    }
    for(int i=1; i<=n; i++) {
        s = find(i);
        d[s]++;
        if(c[i] % 2) o[s]++;
    }
    s = t = 0;
    for(int i=1; i<=n; i++)
        if(d[i] > 1) {
            if(o[i] > 2)
                s += (o[i] - 2) / 2;
            t++;
        }
    printf("%d\n", s + t - 1);
    return 0;
}