#include <algorithm>
#include <cstdio>
#include <iostream>
#include <map>
#include <cmath>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <vector>
#include <stdlib.h>
#include <stdio.h>
#include <bitset>
using namespace std;
#define FOR(I,A,B) for(int I = (A); I < (B); ++I)
typedef long long ll;

int main(){
  int n;
  cin >> n;
  int A[500];
  FOR (i,0,500) A[i] = 0;
  int sum_A = 0;
  FOR (i,0,n) {
    cin >> A[i];
    sum_A += A[i];
  }
  int B[500];
  FOR (i,0,500) B[i] = 0;
  int ans = 999999;
  FOR (i,0,250) {
    int num = 2 * i + 1;
    int b = 1;
    int sum_B = 0;
    FOR (j,0,num) {
      B[j] = b;
      sum_B += b;
      if(j>=num/2) b--;
      else b++;
    }
    if(sum_B > sum_A) break;
    int cnt = 0;
    FOR (j,0,500) {
      cnt += abs(A[j] - B[j]);
    }
    if (sum_A > sum_B) {
      cnt -= sum_A - sum_B;
      cnt /= 2;
      cnt += sum_A - sum_B;
    }
    else {
      cnt /= 2;
    }
    ans = min(ans, cnt);
  }
  cout << ans << endl;
  return 0;
}