import java.io.*;
import java.util.StringTokenizer;

class Main{

static final PrintWriter out=new PrintWriter(System.out);

public static void main(String[] args) throws IOException{
BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
String line="";
while((line=br.readLine())!=null&&!line.isEmpty()){
int n=Integer.parseInt(line);
int[] p=new int[300];
int ans=0;
int total=0;
StringTokenizer st=new StringTokenizer(br.readLine());
for(int i=0;i<n;i++){
p[100+i]=Integer.parseInt(st.nextToken());
total+=p[100+i];
}
int step=(int)Math.sqrt(total);
ans+=total-step*step;
int rem=0;
for(int i=100-step+1;i<100-step+n+1;i++){
int now=0;
for(int j=0;j<2*step-1;j++){
if(j<=step-1) now+=Math.min(j+1,p[i+j]);
else now+=Math.min(2*step-1-j,p[i+j]);
}
rem=Math.max(rem,now);
}
ans+=step*step-rem;
out.println(ans);
out.flush();
}
}
}