from collections import *
from itertools import *
from functools import *
from heapq import *
import sys,math
input = sys.stdin.readline

x0,y0 = map(int,input().split())
N = int(input())
XYW = [tuple(map(float,input().split())) for _ in range(N)]
W = [0 for _ in range(1<<N)]
for i in range(N):
    x,y,w = XYW[i]
    W[(1<<i)]=w

for i in range(N):
    
    msk = (1<<i)
    for j in range(1<<N):
        if (j>>i)&1==0:
            W[j|msk] += W[j]

tW = W[-1]
W = [tW-w for w in W]

INF = (1<<50)
dp = [[INF]*(1<<N) for _ in range(N)]
for j in range(N):
    x,y,w = XYW[j]
    dp[j][1<<j] = (100+W[0])*(abs(x-x0)+abs(y-y0))/120 + w
    
for i in range(1<<N):
    
    source = []
    sink = []
    Weight = W[i]
    for j in range(N):
        if (i>>j)&1:
            source.append(j)
        else:
            sink.append(j)
    
    for s in source:
        xs,ys,ws = XYW[s]
        for t in sink:
            xt,yt,wt = XYW[t]
            dp[t][i|(1<<t)] = min(dp[t][i|(1<<t)],dp[s][i]+(W[i]+100)*(abs(xs-xt)+abs(ys-yt))/120 + wt)
            

ans = INF
w = W[-1]
for i in range(N):
    xi,yi = XYW[i][:2]
    tmp = dp[i][-1] + (100+w)*(abs(xi-x0)+abs(yi-y0))/120
    ans = min(ans,tmp)
print(ans)