def time(w, x1, y1, x2, y2):
    tt = (w + 100) / 120 * (abs(x1 - x2) + abs(y1 - y2))
    return tt


def solve():
    SX, SY = list(map(int, input().split()))
    N = int(input())
    X = [0] * N
    Y = [0] * N
    W = [0] * N

    for i in range(N):
        x, y, w = list(input().split())
        X[i], Y[i], W[i] = int(x), int(y), float(w)

    memo = {}

    def mrec(v, w, c):
        """v: 配達済みの店の集合、w: 今積んでる量(cで下ろし済み)、c:今いる店 = c に移動するまでの時間"""
        if (v, w, c) in memo:
            return memo[v, w, c]

        if v == 0:
            ret = time(w + W[c], SX, SY, X[c], Y[c])
        else:
            mi = 9999999999999
            for i in range(N):
                i1 = 1 << i
                if v & i1 and i != c:
                    # i から来た可能性
                    mi = min(mi, time(w + W[c], X[i], Y[i], X[c], Y[c]) + mrec(v - i1, w + W[c], i))
            ret = mi

        memo[v, w, c] = ret
        return ret


    mi = min(time(0, SX, SY, X[c], Y[c]) + mrec((1 << N) - 1 - (1 << c), 0, c) for c in range(N))
    print(mi + sum(W))


def main():
    solve()


if __name__ == '__main__':
    main()