C++ :

#include <iostream>
#include <fstream>

using namespace std;

int n;
ifstream fin("p1.in");
ofstream fout("p1.out");
double k, s = 0.0;
//#define cin fin
//#define cout fout

main()
{
	cin >> k;
	fin.close();
	
	for (n = 1; s <= k; ++n)
		s += 1.0 / (double)n;
		
	cout << --n;
	fout.close();
//	for(;;);
}

Pascal :

var
  k,n:longint;
  s:real;
begin
  readln(k);
  s:=1;n:=1;
  repeat
    inc(n);
    s:=s+1/n;
  until s>k;
  write(n);
end.

Java :

import java.util.Scanner;
public class Main
{
	static Scanner inputScanner=new Scanner(System.in);
	public static void main(String[] argStrings)
	{
		int k=inputScanner.nextInt();
		double Sn=0;
		int n=0;
		for (double i = 1; Sn<=k; i++)
		{
			Sn+=1/i;
			n=(int)i;
		}
		System.out.println(n);
	}
}