import sys
from itertools import cycle

L = sys.stdin.read().splitlines()
N = L[2:]

M = []
for x in N:
    (a, b) = x.split(" = ")
    c = b.split(", ")
    M.append( (a, c[0].replace("(", ""), c[1].replace(")", "")) )

S = 0
tri = "AAA"

for i in cycle(L[0]) :
    for a, b, c in M:
        if a == tri:
            #print(a, b, c)
            tri = b if i == "L" else c
            break
    S+=1
    if tri == "ZZZ" : break

print(S)