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#include <bits/stdc++.h>
#define FOR(i, a, b) for (int i = (a); i <= (b); ++i)
#define ROF(i, a, b) for (int i = (a); i >= (b); --i)
#define all(x) x.begin(),x.end()
#define CLR(i,a) memset(i,a,sizeof(i))
#define fi first
#define se second
#define pb push_back
#define SZ(a) ((int) a.size())
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<ll,ll> pll;
typedef array<ll,3> arr;
typedef double DB;
typedef pair<DB,DB> pdd;
typedef pair<ll,bool> plb;
constexpr ll MAXN=static_cast<ll>(1e6)+10,INF=static_cast<ll>(5e18)+3;
ll N,M,T,A[MAXN];
vector<ll> g[MAXN];
ll color[MAXN];
ll sum=0;
ll cnt=0;
bool abNormal=false;
void dfs(ll x,ll xcolor){
if(abNormal) return;
if(color[x]!=0 && color[x]!=xcolor){
abNormal=true;
return;
}else if(color[x]!=0){
return;
}
color[x]=xcolor;
sum+=1;
if(xcolor==2) cnt+=1;
for(int i=0;i<g[x].size();++i){
ll v=g[x][i];
dfs(v,3-xcolor);
}
}
inline void solve(){
cin>>N>>M;
FOR(i,1,M){
ll u,v;
cin>>u>>v;
g[u].pb(v);
g[v].pb(u);
}
ll ans=0;
FOR(i,1,N){
if(color[i]!=0) continue;
sum=0;
cnt=0;
abNormal=false;
dfs(i,1);
if(abNormal){
cout<<"Impossible\n";
return;
}
if(cnt>sum-cnt){
ans+=sum-cnt;
}else{
ans+=cnt;
}
}
cout<<ans<<"\n";
}
int main()
{
ios::sync_with_stdio(false);
cin.tie(0);cout.tie(0);
solve();
return 0;
}
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