<?php
    $n = trim(fgets(STDIN));
    if($n == 1){
        echo 0;
        exit;
    }
    $b = 1;
    for($i = 1; $i < $n; $i++){
        $b = $b * 2;
        if($b * 2 > $n){
            break;
        }elseif($b == $n){
            $i++;
            break;
        }
    }
    //echo $i."\n";
    //echo $b."\n";
    
    if($n - $b == 0){
        echo $i;
    }else{
        echo $i + 1;
    }
?>