#include <cstdio>
#include <algorithm>
using namespace std;
typedef long long lint;
struct pole{lint a,i;}d[100005];
int cmp(pole a, pole b){return a.a * b.i < b.a * a.i;}
lint n;
lint trial(lint piv){
lint res = 0;
for (int i=0; i<n; i++) {
res += max(d[i].a - piv * d[i].i, piv * d[i].i - d[i].a);
}
return res;
}
int main(){
scanf("%lld",&n);
for (int i=0; i<n; i++) {
scanf("%lld",&d[i].a);
d[i].i = i;
}
sort(d,d+n,cmp);
int piv;
lint cum = 0;
for (piv = 0; piv < n; piv++) {
cum += d[piv].i;
if(cum > n * (n-1) / 4) break;
}
lint that = d[piv].a / d[piv].i;
printf("%lld",min(min(trial(that-1),trial(that)),trial(that+1)));
}
