#!/usr/local/bin/tclsh

foreach r [split [read stdin] \n] {
    if {[scan $r {%[^=] => %d %s} a b c] != 3} continue
    set qty($c) $b
    foreach i [split [string map {{ } {}} $a] ,] {
	scan $i {%d%s} j k
	lappend inputs($c) [list $j $k]
	set made($c) 0
    }
}
if {[llength $argv] != 1} {
    puts stderr "usage: $argv0 ORE-per-FUEL"
    exit 1
}

proc make {n chem} {
    global qty inputs made
    #puts "making: $n $chem"

    if {$chem eq "ORE"} {
	set made(ORE) [expr {$made(ORE) - $n}]
	if {$made(ORE) < 0} {return 0}
	#puts "$made(ORE) ORE left"
	return 1
    }

    # Find the reaction we need to run, and then calculate how many times
    # to run it.
    if {$n == $qty($chem)} {
	set times 1
    } else {
	set times [expr {($n + $qty($chem) - 1) / $qty($chem)}]
    }
    #puts "make $times batches of $chem"

    # Produce enough of each input chemical.
    # Consume them *as we go* so they don't get double-used.
    foreach i $inputs($chem) {
	lassign $i n2 chem2
	if {$made($chem2) < ($times * $n2)} {
	    if {! [make [expr {($times * $n2) - $made($chem2)}] $chem2]} {
		#puts "making [expr {$times*$n2}] $chem2 failed"
		return 0
	    }
	} else {
	    #puts "already have $made($chem2) $chem2 (need [expr {$times*$n2}])"
	}
	incr made($chem2) [expr {-1 * $times * $n2}]
	#puts "consumed [expr {$times * $n2}] $chem2 ($made($chem2) left)"
    }

    # Inputs have been consumed, so create output.
    incr made($chem) [expr {$times * $qty($chem)}]
    #puts "created [expr {$times * $qty($chem)}] $chem"
    return 1
}

set made(ORE) 1000000000000
set fuel [expr {1000000000000 / [lindex $argv 0]}]
make $fuel FUEL
puts "start with $fuel FUEL, $made(ORE) ORE left"
while {$made(ORE) > 10000000 * [lindex $argv 0]} {
    make 1000000 FUEL
    incr fuel 1000000
    puts ">> $fuel FUEL, $made(ORE) ORE left"
}
while {$made(ORE) > 10000 * [lindex $argv 0]} {
    make 1000 FUEL
    incr fuel 1000
    puts ">> $fuel FUEL, $made(ORE) ORE left"
}
while {[make 1 FUEL]} {
    incr fuel
}
puts "made $fuel FUEL"