import sys
read=sys.stdin.buffer.read
readline=sys.stdin.buffer.readline
readlines=sys.stdin.buffer.readlines

x0, y0=map(float, readline().split())
n=int(readline())
xyw=list(map(float, read().split()))
x=xyw[::3]
y=xyw[1::3]
w=xyw[2::3]
ws=sum(w)
INF=1e9
dp=[[INF]*(1<<n) for _ in range(n)]
for i in range(n):
    dp[i][1<<i]=(abs(x0-x[i])+abs(y0-y[i]))*(ws+100)/120
for i in range(1<<n):
    s=sum(x for j, x in enumerate(w) if i&(1<<j))
    for j in range(n):
        if not i&(1<<j):
            continue
        t=dp[j][i]
        for k in range(n):
            if i&(1<<k):
                continue
            t1=t+(abs(x[j]-x[k])+abs(y[j]-y[k]))*(ws-s+100)/120
            if dp[k][i^(1<<k)]>t1:
                dp[k][i^(1<<k)]=t1
ans=min(dp[i][-1]+(abs(x0-x[i])+abs(y0-y[i]))*100/120+ws for i in range(n))
print('{:.8f}'.format(ans))