import std.algorithm, std.array, std.range;
import std.string, std.conv;
import std.stdio, std.typecons;

void main()
{
  auto n = readln.chomp.to!int;

  auto i = 0;
  auto k = 1;
  while (k < n) {
    i += 1;
    k *= 2;
  }

  writeln(i);
}