#include<bits/stdc++.h>
using namespace std;
#include <atcoder/all>
using namespace atcoder;
using mint=modint998244353; //1000000007;
using ll=long long;
using pp=pair<int,int>;
#define sr string 
#define vc vector
#define fi first
#define se second
#define rep(i,n) for(int i=0;i<(int)n;i++)
#define pb push_back
#define all(v) v.begin(),v.end()
#define pque priority_queue
#define bpc(a) __builtin_popcount(a)
int main(){
  int n;cin>>n;
  vc<int>v(n); rep(i,n)cin>>v[i];
  mint a=1,b=0,c=0;
  rep(i,n){
    if(v[i]==50)c+=a+b+c;
    if(v[i]>50){
      mint aa=a;
      a+=b; b+=aa; c*=2;
    }
    if(v[i]<50){
      a*=2; b*=2; c*=2;
    }
  }
  cout<<b.val();
}