#include <stdio.h>
#include <bits/stdc++.h>
#include <atcoder/all>
using namespace atcoder;
using namespace std;
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define Inf 1000000001
vector<int> A;

struct Data{
	long long v = 0;
	long long sz = 0;
};

Data op(Data a,Data b){
	a.v += b.v;
	a.sz += b.sz;
	return a;
}

Data e(){
	return Data();
}

Data mapping(long long a,Data b){
	if(a==-1)return b;
	b.v = a * b.sz;
	return b;
}

long long composition(long long a,long long b){
	if(a==-1)return b;
	if(b==-1)return a;
	return a;
}

long long id(){
	return -1;
}

int main(){
	
	int N;
	cin>>N;
	
	A.resize(N);
	
	rep(i,N){
		scanf("%d",&A[i]);
	}
	
	vector<int> Nxt(N+1,N);
	vector<int> nxt(N);
	for(int i=N-1;i>=0;i--){
		nxt[i] = Nxt[A[i]];
		Nxt[A[i]] = i;
	}
	
	vector<Data> mexs(N);
	
	set<int> S;
	map<int,int> mp;
	for(int i=1;i<=N+1;i++){
		S.insert(i);
	}
	rep(i,N){
		mp[A[i]]++;
		S.erase(A[i]);
		mexs[i].v = (*S.begin());
		mexs[i].sz = 1;
	}
	
	lazy_segtree<Data,op,e,long long,mapping,composition,id> seg(mexs);
	
	long long ans = 0LL;
	
	rep(i,N){
		ans += seg.prod(i,N).v;
		//cout<<seg.prod(i,N).v<<endl;
		
		int ok = nxt[i],ng = i;
		while(ok-ng>1){
			int mid = (ok+ng)/2;
			if(seg.get(mid).v >= A[i])ok = mid;
			else ng=  mid;
		}
		seg.apply(ok,nxt[i],A[i]);
		
		
	}
	
	cout<<ans<<endl;
	
	
	return 0;
}