#include <bits/stdc++.h>

 using namespace std;

 typedef long long ll;

 #define rep(i, a, b) for (int i = a; i <= b; ++i)

 const int N = 1e5 + ;

 int n, m, vis[N], cnt[], ans;

 bool used[N];

 vector<int> e[N];

 void dfs(int u, int col) {

     if (!used[u]) {

         used[u] = ;

         vis[u] = col;

         cnt[col]++;

         for (auto v : e[u]) {

             dfs(v,  - col);

         }

     }

     else if (col != vis[u]) {

         puts("Impossible");

         exit();

     }

 }

 int main() {

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

     rep(i, , m) {

         int u, v;

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

         e[u].push_back(v);

         e[v].push_back(u);

     }

     rep(i, , n) if (!used[i]) {

         cnt[] = cnt[] = ;

         dfs(i, );

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

     }

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

     return ;

 }