// Validator
#include <atcoder/modint>
#include <iostream>
#include <vector>
#include "testlib.h"
using namespace std;
using mint = atcoder::modint1000000007;

int main(int argc, char **argv) {
    registerValidation(argc, argv);
    int N = inf.readInt(1, 100);
    inf.readEoln();
    vector<int> P = inf.readInts(N, 0, 100);
    inf.readEoln();
    inf.readEof();
    vector<mint> dp(3); // 0: even-dominant, 1: equal, 2: odd-dominant (1 は不要だが…)
    dp[0] = 1;
    for (auto p : P) {
        vector<mint> 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].val() << '\n';
}