[ps]max_depth[pe]
└──[ps]valid_file[pe]
   └──[m0s]s[m0e][m0s]h[m0e][m0s]o[m0e][m0s]u[m0e][m0s]l[m0e][m0s]d[m0e][m0s] [m0e][m0s]s[m0e][m0s]h[m0e][m0s]o[m0e][m0s]w[m0e]
