# binsearch width
# $9 = min(1e9, 2e18/K/N)
$9 = 2000000000000000000
$9 = $9 / K
$9 = $9 / N
if $9 >= 1000000000
    $9 = 1000000000
end

$8 = N * N
$7 = N * K

# $0 = floor( ( sqrt(K^2 + 4) - K ) / 2 )
#    = max x [ 0 <= x ] [ x^2 + NKx <= N^2 ]
while $9 > 1

    # $1 = (next x to test)
    $1 = $9 / 2
    $9 = $9 - $1
    $1 = $0 + $1

    # test x = $1
    # $2 = x^2 + NKx
    $2 = $1 + $7
    $2 = $2 * $1

    if $2 <= $8
        $0 = $1
    end

end

$0 = $0 + N
return $0