package main

import (
	"bufio"
	"fmt"
	"math"
	"os"
	"sort"
	"strconv"
)

func out(x ...interface{}) {
	fmt.Println(x...)
}

var sc = bufio.NewScanner(os.Stdin)

func getInt() int {
	sc.Scan()
	i, e := strconv.Atoi(sc.Text())
	if e != nil {
		panic(e)
	}
	return i
}

func getInts(N int) []int {
	ret := make([]int, N)
	for i := 0; i < N; i++ {
		ret[i] = getInt()
	}
	return ret
}

func getString() string {
	sc.Scan()
	return sc.Text()
}

// min, max, asub, absなど基本関数
func max(a, b int) int {
	if a > b {
		return a
	}
	return b
}

func min(a, b int) int {
	if a < b {
		return a
	}
	return b
}

func asub(a, b int) int {
	if a > b {
		return a - b
	}
	return b - a
}

func abs(a int) int {
	if a >= 0 {
		return a
	}
	return -a
}

func lowerBound(a []int, x int) int {
	idx := sort.Search(len(a), func(i int) bool {
		return a[i] >= x
	})
	return idx
}

func upperBound(a []int, x int) int {
	idx := sort.Search(len(a), func(i int) bool {
		return a[i] > x
	})
	return idx
}

func getf() float64 {
	sc.Scan()
	f, _ := strconv.ParseFloat(sc.Text(), 64)
	return f
}

const inf = 1e15

func main() {
	sc.Split(bufio.ScanWords)
	x0, y0 := getInt(), getInt()
	N := getInt()
	X := make([]int, N+1)
	Y := make([]int, N+1)
	W := make([]float64, N+1)
	X[0], Y[0] = x0, y0
	tot := 0.0
	for i := 1; i <= N; i++ {
		X[i], Y[i], W[i] = getInt(), getInt(), getf()
		tot += W[i]
	}
	N++

	dp := make([][]float64, N)
	for i := 0; i < N; i++ {
		dp[i] = make([]float64, 1<<N)
		for j := 0; j < 1<<N; j++ {
			dp[i][j] = inf
		}
	}
	dp[0][0] = 0

	for mask := 0; mask < 1<<N; mask++ {
		for i := 0; i < N; i++ {
			if dp[i][mask] < 1e15 {
				lw := tot
				for j := 0; j < N; j++ {
					if mask&(1<<j) != 0 {
						lw -= W[j]
					}
				}
				for j := 0; j < N; j++ {
					if mask&(1<<j) == 0 {
						lo := float64(abs(X[j]-X[i]) + abs(Y[j]-Y[i]))
						dp[j][mask|(1<<j)] = math.Min(dp[j][mask|(1<<j)], dp[i][mask]+lo*(lw+100.0)/120+W[j])
					}
				}
			}
		}
	}
	out(dp[0][(1<<N)-1])
}