#include<bits/stdc++.h>
using namespace std;
#include<atcoder/all>
using namespace atcoder;
using ll = long long;
double sx,sy;
int n;
vector<double> x,y,w;

double dp[1<<13][13];

void solve(){
	for(int i = 0;i< (1<<13);i++){
		for(int j = 0;j<13;j++)dp[i][j] = 1e18;
	}
	dp[0][0] = 0;
	for(int bit = 0;bit<(1<<n);bit++){
		for(int j = 0;j<n;j++){
		double t = 100.0/120.0;
		for(int i = 0;i<n;i++){
			if((bit>>i&1)==0){
				t += w[i]/120.0;
			}
		}
		for(int i = 0;i<n;i++){
			if((bit>>i&1)==0){
				double dist = abs(x[i]-x[j])+abs(y[i]-y[j]);
				if(bit==0&&j==0)dist = abs(x[i]-sx) + abs(y[i]-sy);
				dp[bit + (1<<i)][i] = min(dp[bit+(1<<i)][i],dp[bit][j]+t*dist+w[i]);
			}
		}
		}
	}
	double ans = 1e18;
	for(int i = 0;i<n;i++){
		ans = min(ans,abs(x[i]-sx)*100.0/120.0+abs(y[i]-sy)*100.0/120.0+dp[(1<<n)-1][i]);
	}
	printf("%.10lf\n",ans);
}

signed main(){
	cin.tie(nullptr);
	ios::sync_with_stdio(false);
	cin >> sx >> sy;
	cin >> n;
	x = y = w = vector<double>(n);
	for(int i = 0;i<n;i++){
		cin >> x[i] >> y[i] >> w[i];
	}
	solve();
}