/******************************************************************************

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*******************************************************************************/
public class Main
{
	public static void main(String[] args) {
	   
	    int number = 0 , ans = 0 ;
	    int left = 0 , right = number ;
	    while (left <= right ){
	        int mid = (left + right )/ 2 ;
	        if (mid * mid <= number){
	            ans = mid ;
	            left = mid + 1 ;
	        }
	        else 
	        {
	            right = mid - 1 ;
	        }
	    }
	    System.out.print (ans);
	}
}