#include <cstdio>

#include <cstring>

#include <iostream>

#include <algorithm>

#include <vector>

using namespace std;

const int maxn = ;

int n, m;

vector<int> g[maxn];

bool vis[maxn];

int a[maxn],sum[];

bool dfs(int u, int col) {

    vis[u] = true;

    a[u] = col;

    sum[col]++;

    for (int i = ; i < g[u].size(); i++) {

        int v = g[u][i];

        if (vis[v] && a[v] == a[u])

            return false;

        else if (!vis[v]) {

            if (!dfs(v,  - col))

                return false;

        }

    }

    return true;

}

int main() {

    scanf("%d%d", &n, &m);

    for (int i = ; i <= m; i++) {

        int u, v;

        scanf("%d%d", &u, &v);

        g[u].push_back(v);

        g[v].push_back(u);

    }

    int ans = ;

    for (int i = ; i <= n; i++)

        if (!vis[i]) {

            sum[] = sum[] = ;

            if (!dfs(i,)) {

                printf("Impossible\n");

                return ;

            }

            ans += min(sum[], sum[]);

        }

    printf("%d\n", ans);

    return ;

}