from math import sqrt, log10
import sys

class Pipe:
    def __init__(self, p, s, n, l, f=None):
        self.p = p
        self.s = s
        self.f = f
        self.n = n
        self.l = l
        self.children = []

    def __str__(self):
        tabs = ""

        for i in range(1, self.l):
            tabs += "\t"

        s = tabs + self.n + "(" + str(10**self.getFlow()) + ")" + "\n"

        for child in self.children:
            s += str(child)

        return s

    def getFlow(self):
        if self.f != None:
            flow = self.f
            if self.s:
                flow = flow / 2
            return flow

        maxPipe = max(self.children, key=lambda pipe: pipe.getFlow() - pipe.p)
        flow = maxPipe.getFlow() - maxPipe.p
        if self.s:
            flow = flow / 2
        return flow

def readInput(input):
    row_counter = 0
    root = Pipe(1, 0, '1', 1)
    level = {'1':1}

    pipes = { '1': root }

    for row in input:
        if row_counter == 0:
            nodes = int(row)
        elif row_counter == 1 and nodes == 1:
            print(row, end='')
            quit()
        elif row_counter == nodes:
            data = row.split()

            for i in range(0, len(data)):
                flow = int(data[i])

                if flow > 0:
                    pipes[str(i+1)].f = log10(flow)
        else:
            data = row.split()
            from_node, to_node, p, s = data[0], data[1], log10(float(data[2]) / 100), int(data[3])

            if from_node in level:
                level[to_node] = level[from_node] + 1

            pipe = Pipe(p, s, to_node, level[to_node])

            if from_node in pipes:
                pipes[from_node].children.append(pipe)

            pipes[to_node] = pipe

        row_counter += 1

    print('{0:0.4f}'.format(10**root.getFlow()))

input = []
for i in sys.stdin:
    i.strip('\n')
    input.append(i)

readInput(input)