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 = []
for a, b, c in M:
    for d, e, f in a.split():
        if f == "A" : tri.append(a)

#print(tri)

for i in cycle(L[0]) :
    for idx, t in enumerate(tri):
        for a, b, c in M:
            if a == t:
                #print(t, a, b, c)
                tri[idx] = b if i == "L" else c
                break
    S+=1
    #print(tri)
    fin = True
    for a in tri:
        for d, e, f in a.split():
            #print(a, f)
            if f == "Z":
                fin = True and fin
            else:
                fin = False
    if fin: break

print(S)