#include <vector>
#include <list>
#include <map>
#include <set>
#include <deque>
#include <stack>
#include <bitset>
#include <algorithm>
#include <functional>
#include <numeric>
#include <utility>
#include <sstream>
#include <iostream>
#include <iomanip>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <cctype>
#include <string>
#include <cstring>
#include <ctime>
#include <fstream>
#include <queue>
#include <complex>

#define INF 1145141919
#define EPS 1e-9
#define Pi acos(-1)

using namespace std;

typedef long long ll;

#define MAX_N 15

int sx, sy;
int N;
int X[MAX_N], Y[MAX_N];
double W[MAX_N];

double memo[1 << MAX_N][MAX_N];

double solve(int S, int now){
	
	if (memo[S][now] > 0)
		return memo[S][now];

	if (S == (1 << N) - 1)
		return (100.0/120.0)*(double)(abs(sx - X[now]) + abs(sy - Y[now]));

	memo[S][now] = INF;

	double now_W = 0.0;
	for (int i = 0; i < N; i++){
		if (!(S >> i & 1))
			now_W += W[i];
	}

	double ans = INF;

	for (int i = 0; i < N; i++){
		if (S >> i & 1)
			continue;
		if (S == 0)
			ans = min(ans, W[i] + (now_W + 100)*(double)(abs(X[i] - sx) + abs(Y[i] - sy)) / 120 + solve(S | 1 << i, i));
		else
			ans = min(ans, W[i] + (now_W + 100)*(double)(abs(X[now] - X[i]) + abs(Y[now] - Y[i]))/120 + solve(S | 1 << i, i));
	}

	return memo[S][now] = ans;

}

int main(){

	cin >> sx >> sy;
	cin >> N;
	for (int i = 0; i < N; i++){
		cin >> X[i] >> Y[i] >> W[i];
	}

	printf("%.8f\n", solve(0, 0));

	return 0;

}