using System;
using System.Collections;
using System.Collections.Generic;
 
class TEST{
	static void Main(){
		Sol mySol =new Sol();
		mySol.Solve();
	}
}

class Sol{
	public void Solve(){
		
		double Inf=1e16;
		double[][] dp=new double[1<<N][];
		for(int i=0;i<(1<<N);i++){
			dp[i]=new double[N];
			for(int j=0;j<N;j++)dp[i][j]=Inf;
		}
		
		
		
		double[] Sum=new double[1<<N];
		double tot=0;
		for(int i=0;i<N;i++)tot+=W[i];
		for(int i=0;i<(1<<N);i++){
			Sum[i]=tot;
			for(int j=0;j<N;j++){
				if(((i>>j)&1)>0)Sum[i]-=W[j];
			}
		}
		
//for(int i=0;i<(1<<N);i++)Console.Write("{0} ",Sum[i]);Console.WriteLine();

		for(int j=0;j<N;j++){
			dp[1<<j][j]=W[j]+(Math.Abs(X[j]-X0)+Math.Abs(Y[j]-Y0))*(tot+100)/120;
		}
		
		
		for(int s=0;s<(1<<N);s++){
			for(int j=0;j<N;j++){
				if(dp[s][j]==Inf)continue;
				for(int k=0;k<N;k++){
					if(((s>>k)&1)>0)continue;
					dp[s|(1<<k)][k]=Math.Min(dp[s|(1<<k)][k],dp[s][j]+W[k]+(Math.Abs(X[k]-X[j])+Math.Abs(Y[k]-Y[j]))*(Sum[s]+100)/120);
				}
			}
		}
		
		double Ans=Inf;
		for(int i=0;i<N;i++){
			Ans=Math.Min(Ans,dp[(1<<N)-1][i]+(Math.Abs(X[i]-X0)+Math.Abs(Y[i]-Y0))*(0+100.0)/120.0);
		}
		
		Console.WriteLine(Ans);
	}
	
	int X0,Y0;
	int N;
	int[] X,Y;
	double[] W;
	public Sol(){
		var d=ria();
		X0=d[0];Y0=d[1];
		N=ri();
		X=new int[N];
		Y=new int[N];
		W=new double[N];
		for(int i=0;i<N;i++){
			var dd=rsa();
			X[i]=int.Parse(dd[0]);
			Y[i]=int.Parse(dd[1]);
			W[i]=double.Parse(dd[2]);
		}
	}




	static String rs(){return Console.ReadLine();}
	static int ri(){return int.Parse(Console.ReadLine());}
	static long rl(){return long.Parse(Console.ReadLine());}
	static double rd(){return double.Parse(Console.ReadLine());}
	static String[] rsa(){return Console.ReadLine().Split(' ');}
	static int[] ria(){return Array.ConvertAll(Console.ReadLine().Split(' '),e=>int.Parse(e));}
	static long[] rla(){return Array.ConvertAll(Console.ReadLine().Split(' '),e=>long.Parse(e));}
	static double[] rda(){return Array.ConvertAll(Console.ReadLine().Split(' '),e=>double.Parse(e));}
}