#include<bits/stdc++.h>
using namespace std;
const int MODA=1e9+7;
const int MOD1=1000000009,MOD2=993244853;
struct hs
{
	int h1,h2;
	hs operator+(const hs &h)const{return (hs){(h1+h.h1)%MOD1,(h2+h.h2)%MOD2};}
	hs operator-(const hs &h)const{return (hs){(h1-h.h1+MOD1)%MOD1,(h2-h.h2+MOD2)%MOD2};}
	bool operator<(const hs &h)const{return h1==h.h1?h2<h.h2:h1<h.h1;}
};
int main()
{
	ios_base::sync_with_stdio(false);
	cin.tie(0);
	vector<hs> pw(1111111);
	pw[0]=(hs){1,1};
	for(int i=1;i<=1000100;i++)
		pw[i]=pw[i-1]+pw[i-1];
	vector<hs> S(1111111);
	map<hs,int> mp;
	mp[S[0]]=0;
	int n;
	cin>>n;
	vector<int> dp(n+5);
	dp[0]=1;
	int lgn=19;
	vector<pair<int,int>> stk;//pos,val
	vector<int> a(n+5);
	for(int i=1;i<=n;i++)
	{
		cin>>a[i];
		S[i]=S[i-1]+pw[a[i]];
		while(not stk.empty() and stk.back().second<=a[i])
		{
			stk.pop_back();
		}
		stk.emplace_back(i,a[i]);
		int minv=1e9;
		for(auto [p,v]:stk)
		{
			for(int t=v;t<=min(v+lgn,minv-1);t++)
			{
				hs preS=S[i]-pw[t];
				if(mp.find(preS)!=mp.end())
				{
					dp[i]+=dp[mp[preS]];
					dp[i]%=MODA;
				}
			}
			minv=v;
		}
		mp[S[i]]=i;
	}
	cout<<dp[n]<<endl;
	
	return 0;
}