#include<iostream>
#include<stdio.h>
#include<ctype.h>
#define ll long long
#define ld long double
#define fi first
#define se second
#define pii pair<int,int>
#define lowbit(x) ((x)&-(x))
#define popcount(x) __builtin_popcount(x)
#define inf 0x3f3f3f3f
#define infll 0x3f3f3f3f3f3f3f3f
#define umap unordered_map
#define all(x) x.begin(),x.end()
#define mk make_pair
#define pb push_back
#define ckmax(x,y) x=max(x,y)
#define ckmin(x,y) x=min(x,y)
#define rep(i,l,r) for(int i=l;i<=r;++i)
#define per(i,r,l) for(int i=r;i>=l;--i)
#define N 100005
#define int long long
using namespace std;
inline int read(){
	int x=0,f=0; char ch=getchar();
	while(!isdigit(ch)) f|=(ch==45),ch=getchar();
	while(isdigit(ch)) x=(x<<3)+(x<<1)+(ch^48),ch=getchar();
	return f?-x:x;
}
const int mo=1e9+7,P=1e10+19;
inline void red(int &x){x>=mo?x-=mo:0;}
int n,a[N],ans,pre[N];
signed main(){
	while(scanf("%lld",&n)!=EOF){
		ans=0;
		pre[0]=1;
		for(int i=1;i<=n;++i) a[i]=read(),pre[i]=pre[i-1]*a[i]%mo;
		int mul=1;
		for(int i=n;i>=1;--i){
			if((i-1)&1) red(ans+=mo-mul*pre[i-1]%mo);
			else red(ans+=mul*pre[i-1]%mo);
			mul=(P-a[i])%mo*mul%mo;
		}
		printf("%lld\n",ans);
	}
	return 0;
}