#include <cstdio>#include <cmath>#include <algorithm>#include <cstring>using namespace std;const int N=205;const int INF=0x3f3f3f3f;#define CLR(a,v) memset(a,v,sizeof(a))template<typename T>inline T sq(T a){return a*a;}struct Point{int x,y;bool read(){if(scanf("%d%d",&x,&y)==-1)return false;return x!=-1&&y!=-1;}double dist(const Point &rhs){return sqrt(sq(x-rhs.x)+sq(y-rhs.y));}}point[N];double mp[N][N];double dist[N];bool vis[N];int main(){for(int i=0;i<N;i++)for(int j=0;j<N;j++)mp[i][j]=INF;int cnt=0;point[cnt++].read();point[cnt++].read();while(true){if(!point[cnt].read())break;cnt++;for(;point[cnt].read();cnt++)mp[cnt][cnt-1]=mp[cnt-1][cnt]=point[cnt].dist(point[cnt-1])/40000;}for(int i=0;i<cnt;i++)for(int j=0;j<i;j++)if(mp[i][j]==INF)mp[i][j]=mp[j][i]=point[i].dist(point[j])/10000;for(int i=0;i<N;i++)dist[i]=INF;CLR(vis,false);dist[0]=0;for(int i=0;i<cnt;i++){int x=1;for(int j=0;j<cnt;j++)if(!vis[j]&&dist[j]<dist[x])x=j;for(int j=0;j<cnt;j++)dist[j]=min(dist[j],dist[x]+mp[j][x]);if(x==1)break;vis[x]=true;}printf("%.0fn",dist[1]*60);return 0;}
