#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
const long nPrime = 1000000007;
//const long nPrime = 998244353;
typedef long long ll;
int main() {
    long n;
    cin >> n;
    vector<vector<long>> vviDP(3,vector<long>(n+1,0));
    vviDP[1][0] = 1;
    for(long i = 0; i < n; i++){
        long a;
        cin >> a;
        if(a == 50){
            vviDP[0][i+1] = vviDP[0][i];
            vviDP[1][i+1] = vviDP[1][i];
            vviDP[2][i+1] = vviDP[0][i] + vviDP[1][i] + 2 * vviDP[2][i];
        } else if (a > 50){
            vviDP[0][i+1] = vviDP[0][i] + vviDP[1][i];
            vviDP[1][i+1] = vviDP[1][i] + vviDP[0][i];
            vviDP[2][i+1] = 2 * vviDP[2][i];
        } else {
            vviDP[0][i+1] = 2 * vviDP[0][i];
            vviDP[1][i+1] = 2 * vviDP[1][i];
            vviDP[2][i+1] = 2 * vviDP[2][i];
        }
        
        vviDP[0][i+1] %= nPrime;
        vviDP[1][i+1] %= nPrime;
        vviDP[2][i+1] %= nPrime;
    }
    
    cout << vviDP[0][n] << endl;
    return 0;
}