//#define _GLIBCXX_DEBUG
#include <bits/stdc++.h>
#include <iostream>
#include <algorithm>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
using mint = modint1000000007;
using ll = long long;
using pii = pair<int,int>;
using pll = pair<ll,ll>;
using vi = vector<int>;  using vvi = vector<vi>;
using vl = vector<ll>;   using vvl = vector<vl>;
using vb = vector<bool>; using vvb = vector<vb>;
using vm = vector<mint>; using vvm = vector<vm>;
using vpi = vector<pii>; using vvpi = vector<vpi>;
using vpl = vector<pll>; using vvpl = vector<vpl>;
const int inf = 1 << 30;
const ll INF = 1LL << 60;
#define rep(i,m,n) for (int i = m; i < (int)(n); i++)
#define rrep(i,m,n) for (int i = m; i > (int)(n); i--)

int main(){
    int n; cin >> n;
    vi P(n);
    rep(i,0,n){
        cin >> P[i];
    }
    vvm dp(n+1,vm(3));
    dp[0][0] = 1;
    rep(i,0,n){
        dp[i+1][0] += dp[i][0];
        dp[i+1][1] += dp[i][1];
        dp[i+1][2] += dp[i][2];
        if (P[i] < 50){
            dp[i+1][1] += dp[i][1];
            dp[i+1][0] += dp[i][0];
        }
        else if (P[i] > 50){
            dp[i+1][0] += dp[i][1];
            dp[i+1][1] += dp[i][0];
        }
        else{
            dp[i+1][2] += dp[i][1] + dp[i][0];
        }
    }
    cout << dp[n][1].val() << endl;
}