#include<iostream>

#include<cstdio>

#include<cstring>

#define N 100009

#define LL long long

#define mod 12345678910LL

using namespace std;

int n,top;

int sta[N],pos[N];

LL dfs(int l,int r){

    LL ret=;

    int rr=pos[l];

    if(rr-l==)ret=(ret%mod+%mod)%mod;

    if(l!=rr-)ret=(ret%mod+*dfs(l+,rr-)%mod)%mod;

    if(rr+<=r)ret=(ret%mod+dfs(rr+,r)%mod)%mod;

    return ret%mod;

}

int main(){

    scanf("%d",&n);

    for(int i=;i<=n;i++){

        int x;

        scanf("%d",&x);

        if(x==)

         sta[++top]=i;

        else

         if(top)

          pos[sta[top--]]=i;

    }

    cout<<dfs(,n);

    return ;

}