#!/usr/bin/env python


def read_input():
    with open('input.txt', 'r') as f:
        data  = f.read().splitlines()
        return [ int(x) for x in data[0].split(" ")]


def get_node_meta(data, pos):
    num_ch = data[pos]
    num_m = data[pos+1]
    len_ch = 0	# total length of children
    meta = []

    for ch in range(num_ch):
        (ch_len, ch_meta) = get_node_meta(data, pos+2+len_ch)
        len_ch += ch_len
        meta = meta + ch_meta

    meta = meta + data[pos+2+len_ch:pos+2+len_ch+num_m]
    return (len_ch+2+num_m, meta)

tree = read_input()
(_, meta) = get_node_meta(tree, 0)
print(sum(meta))