#!/bin/python3

import re
import sys
from pprint import pprint 
from collections import Counter
import numpy as np

input_f  = sys.argv[1]

def pp(x):
    for i in x:
        for j in i:
            print(j)
        print()

d, *maps = open(input_f).read().split('\n')


class Node():
    def __init__(self,value,left,right):
        self.value = value
        self.left = left
        self.right = right

s = []
l = []
r = []

maps = maps

nodes = {}

for i in maps:
    if i == '':
        continue
    s = i[:3]
    l = i[7:10]
    r = i[12:15]
    nodes[s] = Node(s,l,r)

current = 'AAA'
steps = 0
count = 0
try:
    while current != 'ZZZ':
        steps += 1
        current = nodes[current].left if d[count%len(d)] == 'L' else nodes[current].right
        count += 1
    print(steps)
except:
    print()


current = {}
for i in nodes:
    if i.endswith('A'):
        current[i] = i

#while not current.endswith('Z'):