#include <bits/stdc++.h>

using namespace std;

#define REP(i,n) for(int i=0; i<(int)(n); i++)
#define FOR(i,b,e) for (int i=(int)(b); i<(int)(e); i++)
#define ALL(x) (x).begin(), (x).end()

const double PI = acos(-1);

int n;
int y[1000];
int dp[1000][10000+1];


int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);

  cin >> n;
  REP (i, n) cin >> y[i];

  for (int h = 0; h <= 10000; h++)
    dp[0][h] = abs(h - y[0]);

  for (int i = 1; i < n; i++) {
    for (int h = 0; h <= 10000; h++) {
      dp[i][h] = dp[i-1][h] + abs(h - y[i]);
      if (h > 0) {
        if (y[i] > h-1)
          dp[i][h] = min(dp[i][h], dp[i][h-1] - 1);
        else
          dp[i][h] = min(dp[i][h], dp[i][h-1] + 1);
      }
    }
  }

  int ret = 1<<30;
  for (int h = 0; h <= 10000; h++)
    ret = min(ret, dp[n-1][h]);
  cout << ret << endl;
  
  return 0;
}