#include <bits/stdc++.h>   using namespace std;   int a[3222], b[32222];   long long dp[3333][3333];   int main() {     int n;     cin >> n;     for (int i = 1; i <= n; i++) {       int x;       cin >> a[i];       a[i] -= i;       b[i] = a[i];     }     sort(b + 1, b + n + 1);     for (int i = 1; i <= n; i++) {       dp[i][1] = dp[i - 1][1] + abs(a[i] - b[1]);       for (int j = 2; j <= n; j++)         dp[i][j] = min(dp[i][j - 1], dp[i - 1][j] + abs(a[i] - b[j]));     }     cout << dp[n][n] << endl;     return 0;   }   