#!/bin/bash

read input
input=( $(sed 's/\(.\)/ \1 /g' <<< $input) )
bits=()
cursor=0
registers=()

for input_char in ${input[@]}; do
  case $input_char in
    '0') bits+=( 0 0 0 0 ) ;;
    '1') bits+=( 0 0 0 1 ) ;;
    '2') bits+=( 0 0 1 0 ) ;;
    '3') bits+=( 0 0 1 1 ) ;;
    '4') bits+=( 0 1 0 0 ) ;;
    '5') bits+=( 0 1 0 1 ) ;;
    '6') bits+=( 0 1 1 0 ) ;;
    '7') bits+=( 0 1 1 1 ) ;;
    '8') bits+=( 1 0 0 0 ) ;;
    '9') bits+=( 1 0 0 1 ) ;;
    'A') bits+=( 1 0 1 0 ) ;;
    'B') bits+=( 1 0 1 1 ) ;;
    'C') bits+=( 1 1 0 0 ) ;;
    'D') bits+=( 1 1 0 1 ) ;;
    'E') bits+=( 1 1 1 0 ) ;;
    'F') bits+=( 1 1 1 1 ) ;;
  esac
done

function parse_packet() {
  local version=$((2#${bits[$((cursor))]}${bits[$((cursor+1))]}${bits[$((cursor+2))]}))
  local packet_type=$((2#${bits[$((cursor+3))]}${bits[$((cursor+4))]}${bits[$((cursor+5))]}))
  cursor=$((cursor+6))
  case $packet_type in
    '4')
      local binary_value='2#'
      local end_reached=0
      while [ $end_reached -eq 0 ]; do
        if [ ${bits[$cursor]} -eq 0 ]; then
          end_reached=1
	fi
        local binary_block=${bits[@]:$((cursor+1)):4}
        binary_value=$binary_value${binary_block// /}
        cursor=$((cursor+5))
      done
      registers+=( $((binary_value)) )
      ;;

    *)
      local length_type=${bits[$cursor]}
      cursor=$((cursor+1))
      if [ $length_type -eq 0 ]; then
	local subpackets_length_arr=${bits[@]:$cursor:15}
        local subpackets_length=$((2#${subpackets_length_arr// /}))
	cursor=$((cursor+15))
        local curr_cursor=$cursor
	local i
	while [ $cursor -lt $((curr_cursor+subpackets_length)) ]; do
	  parse_packet
	  i=$((i+1))
	done
      else
	local subpackets_num_arr=${bits[@]:$cursor:11}
        local subpackets_num=$((2#${subpackets_num_arr// /}))
	local i
	cursor=$((cursor+11))
	for ((i=0;i<subpackets_num;i++)); do
	  parse_packet
	done
      fi
      local j
      case $packet_type in
	'0')
          local result=0
	  for ((j=-1; j>=-i; j--)); do
            result=$((result+registers[-1]))
	    unset registers[-1]
	  done
	  ;;
	'1')
	  local result=1
	  for ((j=-1; j>=-i; j--)); do
            result=$((result*registers[-1]))
	    unset registers[-1]
	  done
	  ;;
	'2')
	  local result=${registers[-1]}
          unset registers[-1]
	  for ((j=-2; j>=-i; j--)); do
	    if [ ${registers[-1]} -lt $result ]; then
              result=${registers[-1]}
	    fi
	    unset registers[-1]
	  done
	  ;;
	'3')
	  local result=${registers[-1]}
          unset registers[-1]
	  for ((j=-2; j>=-i; j--)); do
	    if [ ${registers[-1]} -gt $result ]; then
              result=${registers[-1]}
	    fi
	    unset registers[-1]
	  done
	  ;;
	'5')
	  if [ ${registers[-2]} -gt ${registers[-1]} ]; then
	    local result=1
	  else
	    local result=0
	  fi
	  unset registers[-1]
	  unset registers[-1]
	  ;;
	'6')
	  if [ ${registers[-2]} -lt ${registers[-1]} ]; then
	    local result=1
	  else
	    local result=0
	  fi
	  unset registers[-1]
	  unset registers[-1]
	  ;;
	'7')
	  if [ ${registers[-2]} -eq ${registers[-1]} ]; then
	    local result=1
	  else
	    local result=0
	  fi
	  unset registers[-1]
	  unset registers[-1]
	  ;;
      esac
      registers+=( $result )
      ;;
  esac
}

parse_packet 

echo $registers