import java.util.*;
public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		
		long nn = sc.nextLong();
		long tmp=0;
		long min_num = nn;
		
		for(long i=2;i<=Math.sqrt(nn);i++){
			if(nn%i==0){
				tmp = (long)nn/i;
				if((tmp+i)<min_num){
					min_num = tmp+i;
				}
			}
		}
		
		if(tmp==0){
			System.out.print(nn-1);
		}else{
			System.out.print(min_num-2);
		}
	}	
}
/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz