// Overflow で WA になるはず
#include <iostream>
#include <vector>
using namespace std;
constexpr unsigned md = 1000000007;

int main() {
    int N;
    cin >> N;
    vector<unsigned long long> dp(3); // 0: even-dominant, 1: equal, 2: odd-dominant (1 は不要だが…)
    dp[0] = 1;
    while (N--) {
        int p;
        cin >> p;
        vector<unsigned long long> nxtdp = dp;
        if (p < 50) {
            nxtdp[0] += dp[0];
            nxtdp[1] += dp[1];
            nxtdp[2] += dp[2];
        } else if (p == 50) {
            nxtdp[1] += dp[0] + dp[1] + dp[2];
        } else {
            nxtdp[0] += dp[2];
            nxtdp[1] += dp[1];
            nxtdp[2] += dp[0];
        }
        dp = nxtdp;
    }
    cout << dp[2] % md << '\n';
}