// Arup Guha
// 5/29/2016
// Solution to 2016 February USACO Gold Problem: Circular Barn

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

public class cbarn {

	public static void main(String[] args) throws Exception {

		// Read in data - store two copies.
		BufferedReader stdin = new BufferedReader(new FileReader("cbarn.in"));
		int n = Integer.parseInt(stdin.readLine());
		int[] data = new int[2*n];
		for (int i=0; i<n; i++)
			data[i] = Integer.parseInt(stdin.readLine());
		for (int i=n; i<2*n; i++)
			data[i] = data[i-n];

		// Find the "lowest point", ie the prefix with the lowest sum minus number of terms.
		int min = data[0], minI = 0, sum = 0;
		for (int i=0; i<n; i++) {
			sum += data[i];
			sum--;
			if (sum < min) {
				min = sum;
				minI = i;
			}
		}

		// This shifted array always has a prefix sum if i items i or greater.
		int[] use = new int[n];
		for (int i=minI+1; i<=minI+n; i++)
			use[i-minI-1] = data[i];

		// Store result here.
		long cost = 0;
		int last = n-1;

		// Now go backwards.
		for (int i=n-1; i>=0; i--) {

			// We have a cow here.
			if (use[i] != 0) continue;

			// Go back until we find the next "extra" cow.
			while (last >= i) last--;
			while (last >= 0 && use[last] == 0) last--;
			if (last == -1) break;

			// Move this cow and add its cost.
			use[last]--;
			use[i]++;
			cost = cost + ((long)(last-i))*(last-i);	
		}		

		// Write result.
		PrintWriter out = new PrintWriter(new FileWriter("cbarn.out"));
		out.println(cost);
		out.close();
		stdin.close();
	}
}