#include<iostream>
#include<algorithm>
#include<map>
#include<vector>
#include<cassert>
using namespace std;
struct dat{
	long long Lc,Rc,Ls,Rs;
	map<int,int>cnt;
	int val;
	dat(){}
	dat(int v):Lc(0LL),Rc(0LL),Ls(0LL),Rs(0LL),val(v)
	{
		cnt.clear();
		cnt[v]=1;
	}
	long long need()
	{
		return Rs-Rc*val+Lc*val-Ls;
	}
	bool dec()
	{
		long long now=need();
		long long nLc=Lc,nRc=Rc,nLs=Ls,nRs=Rs;
		if(cnt.find(val)!=cnt.end())
		{
			int c=cnt[val];
			nRc+=c;
			nRs+=(long long)c*val;
		}
		if(cnt.find(val-1)!=cnt.end())
		{
			int c=cnt[val-1];
			nLc-=c;
			nLs-=(long long)c*(val-1);
		}
		long long nxt=nRs-nRc*(val-1)+nLc*(val-1)-nLs;
		if(nxt<=now)
		{
			val--;
			Lc=nLc;
			Rc=nRc;
			Ls=nLs;
			Rs=nRs;
			return true;
		}
		else return false;
	}
};
void merge(dat&l,dat&r)
{
	assert(l.val==r.val);
	l.Lc+=r.Lc;
	l.Rc+=r.Rc;
	l.Ls+=r.Ls;
	l.Rs+=r.Rs;
	if(l.cnt.size()<r.cnt.size())l.cnt.swap(r.cnt);
	for(pair<int,int>p:r.cnt)l.cnt[p.first]+=p.second;
}
int N,A[2<<17];
int main()
{
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	cin>>N;
	for(int i=0;i<N;i++)cin>>A[i];
	sort(A,A+N);
	for(int i=0;i<N;i++)A[i]-=i;
	vector<dat>S;
	S.push_back(dat(A[0]));
	for(int i=1;i<N;i++)
	{
		if(S.back().val<A[i])
		{
			S.push_back(dat(A[i]));
		}
		else
		{
			int v=S.back().val;
			if(v>A[i])S.back().Lc++,S.back().Ls+=A[i];
			S.back().cnt[A[i]]++;
			while(S.back().dec())
			{
				if(S.size()>=2&&S[S.size()-2].val==S.back().val)
				{
					merge(S[S.size()-2],S.back());
					S.pop_back();
				}
			}
		}
	}
	long long ans=0;
	for(int i=0;i<S.size();i++)ans+=S[i].need();
	cout<<ans<<endl;
}