BAMBOOFOX tree

from os import chdir
from glob import glob

def dfs(s):
    s = s[0]
    #print('s = ', s)
    typ = s[-1]
    #print(typ)
    if typ == '+':
        return dfs(glob(s+"/0_*")) + dfs(glob(s+"/1_*"))
    if typ == 'x':
        return dfs(glob(s+"/0_*")) * dfs(glob(s+"/1_*"))
    if typ == 'r':
        #print('path = ', s)
        return int(open(s).read())
for i in range(37):
    chdir("flag["+str(i)+"]/")
    print(chr(dfs(glob("0_*"))), end = '')
    chdir("..")