#include<stdio.h>
int  main()
{
	int n,k;
	double s,a;
	s = 0;
	scanf("%d", &k);
	for (n = 1; s <=k; n++)
	{
		a =1+s+1/n;
		s = a;
	}
		printf("%d", n);
	return 0;
}