#include<bits/stdc++.h>
#define INF 1e9
using namespace std;
const int N=500;
int n,m;
double x[N],y[N];
struct zjy
{
	int to;
	double wide;
	zjy(int tv=0,double tc=0):
		to(tv),wide(tc){}
};
typedef pair<int,double> P;
double dist[N];
double dist2[N];
vector<zjy> G[N];
double verb(int p,int q)
{
	return 1.00*sqrt(1.00*(x[p]-x[q])*(x[p]-x[q])+1.00*(y[p]-y[q])*(y[p]-y[q]));
}
void dfs()
{
	fill(dist,dist+N,INF);
	fill(dist2,dist2+N,INF);
	priority_queue<P, vector<P>, greater<P> > Q;
	dist[0]=0;
	Q.push(P(0,0));
	while(!Q.empty())
	{
		P u=Q.top();
		Q.pop();
		int v=u.first;
		double d=u.second;
		if(dist2[v]<d)
		{
			continue;
		}
		for(unsigned i=0;i<G[v].size();++i)
		{
			zjy &e=G[v][i];
			double d2=d+e.wide;
			if(dist[e.to]>d2)
			{
				swap(dist[e.to],d2);
				Q.push(P(e.to,dist[e.to]));
			}
			if(dist2[e.to]>d2&&dist[v]<d2)
			{
				dist2[e.to]=d2;
				Q.push(P(e.to,dist2[e.to]));
			}
		}
	}
	printf("%.2lf\n",dist2[n-1]);
}
int main()
{
	scanf("%d%d",&n,&m);
	for(int i=1;i<=n;i++)
	{
		cin>>x[i]>>y[i];
	}
	for(int i=1;i<=m;i++)
	{
		int p,q;
		scanf("%d%d",&p,&q);
		G[p-1].push_back(zjy(q-1,verb(p,q)));
	//	printf("%.2lf\n",verb(p,q));
		G[q-1].push_back(zjy(p-1,verb(p,q)));
	}
	dfs();
	return 0;
}