R=range;I=lambda:map(float,raw_input().split());x,y=I();N=input()
M=10**6;U=1<<N;A=[I() for i in R(N)]+[[x,y,0]]
D=[N*[M]for i in R(U)];W=[0]*U;W[0]=sum(A[i][2]for i in R(N))
f=lambda i,j,k:(abs(A[i][0]-A[j][0])+abs(A[i][1]-A[j][1]))*(W[k]+100)/120+A[j][2]
for i in R(N):D[1<<i][i]=f(N,i,0);W[1<<i]=W[0]-A[i][2]
for i in R(U):
	for j in R(N):
		b=1<<j;n=i+b
		if i&b:continue
		W[n]=W[i]-A[j][2]
		for k in R(N):
			if D[i][k]==M:continue
			D[n][j]=min(D[n][j],D[i][k]+f(k,j,i))
print min(D[U-1][i]+f(i,N,U-1)for i in R(N))