package main

import (
	"bufio"
	"fmt"
	"io"
	"os"
)

func solve(in io.Reader, out, err io.Writer) {
	num, i := 0, 0
	fmt.Fscan(in, &num)
	for count := 1; count < num; i, count = i+1, count*2 {
	}

	fmt.Fprintln(out, i)
}

func main() {
	br := bufio.NewReaderSize(os.Stdin, int(1e2))
	solve(br, os.Stdout, os.Stderr)
}