#include <bits/stdc++.h>
#define rep(i,n) for (int i = 0; i < (n); i ++)
using namespace std;
using ll = long long;
using PL = pair<ll,ll>;
using P = pair<int,int>;
constexpr int INF = 1000000000;
constexpr long long HINF = 1000000000000000;
constexpr long long MOD = 1000000007;
constexpr double EPS = 1e-4;
constexpr double PI = 3.14159265358979;
constexpr int H = 20000;

int main() {
    int N; cin >> N;
    vector<ll> Y(N);
    rep(i,N) cin >> Y[i];
    
    vector<vector<ll>> dp(N + 1,vector<ll>(H,INF));
    rep(i,N) {
        if (i == 0) {
            rep(j,H) {
                if (j == 0) dp[i + 1][j] = abs(j - Y[i]);
                else dp[i + 1][j] = min(dp[i + 1][j - 1],abs(j - Y[i]));
            }
        }
        else {
            rep(j,H) {
                if (j == 0) dp[i + 1][j] = dp[i][j] + abs(j - Y[i]);
                else dp[i + 1][j] = min(dp[i + 1][j - 1],dp[i][j] + abs(j - Y[i]));
            }
        }
    }
    
    ll ans = HINF;
    rep(i,H) {
        ans = min(ans,dp[N][i]);
    }
    cout << ans << endl;
    return 0;
}