| #include <iostream> #include <cstdio>
 #include <iomanip>
 #include <fstream>
 using namespace std;
 int main(){
 freopen("p1031.in","r",stdin);
 freopen("p1031.out","w",stdout);
 int n,i=-1,k=0,s=0;
 cin>>n ;
 while(s<n){
 i+=2;
 k+=2;
 s=s+i;
 };
 cout<<k ;
 fclose(stdin);
 fclose(stdout);
 return 0;
 }
 (  )
 |