#include<bits/stdc++.h>
using namespace std;
typedef long long LL;
int n,a[5000],up,down;
int ans,dp[5000][5000];
int main(){
    freopen("HSshu.in","r",stdin);
    freopen("HSshu.out","w",stdout);
    std::cin>>n;
    down=ans=1919810;
    for(int i=1;i<=n;i++){
        scanf("%d",&a[i]);
        up=max(up,a[i]);
        down=min(down,a[i]);
    }
    up=up+n-1;down=max(0,down-n+1);
    for(int i=1;i<=n;i++){
        for(int j=down;j<=up;j++){
            dp[i][j]=1919810;
            for(int k=0;k<j;k++)
                dp[i][j]=min(dp[i][j],dp[i-1][k]+abs(a[i]-j));
        }
    }
    for(int i=down;i<=up;i++){
        ans=min(ans,dp[n][i]);
    }
    std::cout<<ans;
    return 0;
}