C :

#include<stdio.h>
void main()
{
	int N,i,count=0;
    while (scanf("%d",&N)!=EOF)
	{	
		for(i=1;i<=N;i++)
	{	
    	
		if(i*i<=N)
		count+=1;
		else
		break;	
}printf("%d\n",count);
		count=0;
	}

}

C++ :

#include <iostream>
#include <cstdio>
#include <cmath>
using namespace std;
int main()
{

    int a;
    while(scanf("%d",&a)!=EOF)
    {
        int b=sqrt(a);
       cout<<b<<endl;

    }
    return 0;
}