#include <bits/stdc++.h>
#define rep(i, l, r) for (int i = (l); i < (r); i++)
using namespace std;

typedef long long ll;

int main() {
    int N, A = 0, P;
    cin >> N;
    vector<int> Q(0);
    rep(i, 0, N) {
        cin >> P;
        if (P != 50) Q.push_back(P);
    }
    ll W = 0, L = 0, MOD = 1000000007;
    if (Q.size() == 0) {
        cout << 0 << endl;
        return 0;
    }
    if (Q[0] < 50) L = 1;
    else W = 1;
    rep(i, 1, Q.size()) {
        if (Q[i] < 50) {
            int w0 = W * 2 % MOD, l0 = (L * 2 + 1) % MOD;
            W = w0;
            L = l0;
        } else {
            int w0 = (L + W + 1) % MOD, l0 = (L + W) % MOD;
            W = w0;
            L = l0;
        }
    }
    cout << W << endl;
}