#include <iostream>
#include <vector>
#include <cstdio>
#include <cstring>
#include <cmath>
#include <string>

using namespace std;

int n;
int have[500];

const int MX = 1500;
int MX_BAS = 60;

int dp[2][MX + 20][2 * MX + 100];

const int MID = MX + 50;

int abs(int val) {
  return val > 0 ? val : -val;
}
int s[410];
int sum = 1500;

void prep() {
for (int i=2; i<=400; i++) {
  for (int mx = 1500; mx >=0; mx--) {
    int cur = 0;
    int add = mx;
    bool can = true;
    for (int u=0; u<i; u++) {
      cur += add;
      if (cur > sum) {
	can = false;
	break;
      }
      add--;
      if (add < 0) add = 0;
    }
    if (can) {
      s[i] = mx + 1;
      break;
    }
  }
 }
}


int main() {

  cin >> n;
  int sum = 0;

  for (int i = 0; i < n; i++) {
    cin >> have[i];
    sum += have[i];
  }

  for (int j = 0; j <= MX; j++) {
    for (int k = -MX; k <= MX; k++) {
      dp[0][j][MID + k] = 1000000000;
    }
  }
  int curSum = 0;
  prep();
  MX_BAS = 1500;
  //cout << MX_BAS << endl;

  for (int i = 0; i <= MX_BAS; i++) {
    dp[0][i][MID + have[0] - i] = abs(have[0] - i);
  }
  for (int i = 0; i < n - 1; i++) {
    int cm = i & 1;
    for (int j = 0; j <= MX_BAS; j++) {
      for (int k = -MX; k <= MX; k++) {
	dp[cm ^ 1][j][MID + k] = 1000000000;
      }
    }
    for (int j = 0; j <= MX_BAS; j++) {
      for (int k = -MX; k <= MX; k++) {
	for (int f = -1; f < 2; f++) {
	  if (j + f >= 0) {
	    int fre = k + have[i + 1] - j - f;
	    dp[cm ^ 1][j + f][MID + fre] = min(dp[cm ^ 1][j + f][MID + fre], dp[cm][j][k + MID] + abs(fre));
	  }
	}
      }
    }
  }

  int res = 1000000000;
  for (int i = 0; i <= MX_BAS; i++) {
    res = min(res, dp[(n - 1) & 1][i][MID]);
  }
  cout << res << endl;

  return 0;
}