/*
TASK: minitime
LANG: C
Rumen Hristov
*/
#include <stdio.h>

#define MAXN 1<<6;

int n;

int del(int d)
{
	if (d==1) return n;
	if (n%d==0) return d+(n/d);
	return d+(n/d)+1;
}

int main()
{
	scanf("%d",&n);
	int i=1;
	int br=0;
	int res=MAXN;
	
	for (i=1;i<=n;i++)
	{
		br=del(i);
		//printf("%d\n",br);
		if (br<res) res=br;
	}

	printf("%d\n",res);

	return 0;
}