1 #include <bits/stdc++.h>
2 #define _for(i,a,b) for(int i = (a);i < b;i ++)
3 #define _rep(i,a,b) for(int i = (a);i > b;i --)
4 #define INF 0x3f3f3f3f
5 #define pb push_back
6 typedef long long ll;
7 using namespace std;
8 inline ll read()
9 {
10 ll ans = 0;
11 char ch = getchar(), last = ' ';
12 while(!isdigit(ch)) last = ch, ch = getchar();
13 while(isdigit(ch)) ans = (ans << 1) + (ans << 3) + ch - '0', ch = getchar();
14 if(last == '-') ans = -ans;
15 return ans;
16 }
17 inline void write(ll x)
18 {
19 if(x < 0) x = -x, putchar('-');
20 if(x >= 10) write(x / 10);
21 putchar(x % 10 + '0');
22 }
23
24 #define pb push_back
25 const int maxn = 100003;
26 vector<int> G[maxn];
27 int ans = 0;
28 int V;
29 int color[maxn];
30 int a,b;
31 bool dfs(int v,int c)
32 {
33 color[v] = c;
34 if(c==1)
35 a ++;
36 else
37 b ++;
38 for(int i = 0;i < G[v].size();i ++)
39 {
40 if(color[G[v][i]] == c) return false;
41 if(color[G[v][i]] == 0 && !dfs(G[v][i],-c)) return false;
42 }
43 return true;
44 }
45 int biGraph()
46 {
47 memset(color,0,sizeof(color));
48 for(int i = 1;i < V+1;i ++)
49 {
50 a = 0,b = 0;
51 if(color[i]==0)
52 if(!dfs(i,1))
53 return 0;
54 ans += min(a,b);
55 }
56 return 1;
57 }
58 int M;
59
60 int main()
61 {
62 V = read();
63 M = read();
64
65 _for(i,0,M)
66 {
67 int a = read(),b = read();
68 G[a].pb(b);
69 G[b].pb(a);
70 }
71
72 int rnt = biGraph();
73 int rnt1 = 0,rnt2 = 0;
74 if(!rnt)
75 {
76 printf("Impossible\n");
77 return 0;
78 }
79 else
80 printf("%d\n",ans);
81
82 return 0;
83 }
