#include<cmath>
#include<cstdio>
#include<algorithm>
#include<queue>
using namespace std;
typedef long long LL;
int n,m;
LL a[100000+10];
int par[100000+10];
priority_queue<LL> mini[100000+10];

int fpar(int x){
	if (par[x]==-1)return x;
	par[x]=fpar(par[x]);
	return par[x];
}
priority_queue <LL > pq1;
LL ans=0;
int main(){
	scanf("%d%d",&n,&m);
	for (int f1=0;f1<n;f1++)scanf("%lld",&a[f1]);
	for (int f1=0;f1<n;f1++){par[f1]=-1;}
	for (int f1=0;f1<m;f1++){
		int i,j;
		scanf("%d%d",&i,&j);
		i=fpar(i);
		j=fpar(j);
		par[j]=i;
	}
	for (int f1=0;f1<n;f1++){
		int j=fpar(f1);
		mini[j].push(-a[f1]);
	}
	if (n==1+m){
		printf("0\n");
		return 0;
	}
	for (int f1=0;f1<n;f1++){
		if (par[f1]==-1){
			ans-=mini[f1].top();
			mini[f1].pop();
			while (!mini[f1].empty()){
				pq1.push(mini[f1].top());
				mini[f1].pop();
			}	
		}
	}
	
	if (int(pq1.size())>=n-m-2){
		for (int f1=1;f1<=n-m-2;f1++){
			ans-=pq1.top();
			pq1.pop();
		}
		printf("%lld\n",ans);
	} else printf("Impossible\n");
}
