x0, y0 = map(int, input().split())
n = int(input())
XYW = []
for _ in range(n):
    x, y, w = map(float, input().split())
    x = int(x)
    y = int(y)
    XYW.append((x, y, w))

W = [0 for _ in range(1 << n)]
for bit in range(1 << n):
    w = 0
    for i in range(n):
        if (bit >> i) & 1 == 0:
            w += XYW[i][2]
    W[bit] = w
INF = 10**18
DP = [[INF for _ in range(n)] for _ in range(1 << n)]
for i in range(n):
    xi, yi, w = XYW[i]
    bit = 1 << i
    DP[bit][i] = (W[0] + 100) * (abs(xi - x0) + abs(yi - y0)) / 120 + w
for bit in range(1 << n):
    source, sink = [], []
    for i in range(n):
        if (bit >> i) & 1 == 0:
            sink.append(i)
        else:
            source.append(i)
    w = W[bit]
    for s in source:
        xs, ys = XYW[s][:2]
        for t in sink:
            xt, yt, ww = XYW[t]
            nbit = bit | (1 << t)
            DP[nbit][t] = min(DP[nbit][t], DP[bit][s] + (100 + w) * (abs(xt - xs) + abs(yt - ys)) / 120 + ww)
ans = INF
for i in range(n):
    xi, yi = XYW[i][:2]
    ans = min(ans, DP[-1][i] + 100 * (abs(x0 - xi) + abs(y0 - yi)) / 120)
print(ans)