X,Y=map(int,input().split())
N=int(input())
B=[list(map(float,input().split())) for i in range(N)]

for i in range(N):
    B[i][0]=int(B[i][0])
    B[i][1]=int(B[i][1])

DP=[[1<<60]*(N+1) for j in range(1<<N)]
DP[0][0]=0


DIS=[[0]*(N+1) for i in range(N+1)]

Z=[[X,Y]]

for i in range(N):
    Z.append([B[i][0],B[i][1]])

for i in range(N+1):
    for j in range(N+1):
        DIS[i][j]=DIS[j][i]=abs(Z[i][0]-Z[j][0])+abs(Z[i][1]-Z[j][1])

# DP[i][j]でiの店に既にいっていて、今j

for i in range(1<<N):
    for j in range(N+1):
        NOW=0
        for k in range(N):
            if i & (1<<k) == 0:
                NOW+=B[k][2]

        #print(i,NOW)

        for k in range(N):
            if i & (1<<k) == 0:
                DP[i|(1<<k)][k+1]=min(DP[i][j]+DIS[j][k+1]*(NOW+100)/120+B[k][2],DP[i|(1<<k)][k+1])

        #print(DP)

ANS=1<<60

for i in range(1,N+1):
    now=DP[-1][i]
    ANS=min(ANS,now+DIS[i][0]*100/120)

print(ANS)