#include<iostream>#include<string>#include<cmath>#include<algorithm>#include<stdlib.h>#include<stdio.h>using namespace std;struct node{ double x,y; double val; };double pt[1010];int main(){ int n,i,k,j; while(cin>>n&&n) { node *tar=new node[n+3]; double *dp=new double[n+3]; for(i=1;i<=n;i++) { cin>>tar[i].x>>tar[i].y>>tar[i].val; } tar[0].x=0; tar[0].y=0; tar[0].val=0; tar[n+1].x=100; tar[n+1].y=100; dp[0]=0;memset(pt,0,sizeof(pt)); for(i=1;i<=n+1;i++) {pt[i]=pt[i-1]+tar[i].val; double min1=10000000; for(j=0;j<i;j++) { double d=dp[j];d+=pt[i-1]-pt[j];if(d>min1)continue; d+=(sqrt((double)(tar[i].x-tar[j].x)*(tar[i].x-tar[j].x)+(tar[i].y-tar[j].y)*(tar[i].y-tar[j].y))); if(d<min1) min1=d; } dp[i]=min1+1; } printf("%.3lfn",dp[n+1]); delete []tar; delete []dp; } return 0;}
