#include <iostream>
using namespace std;

int main() {
    int n0 = 0, n1 = 0, N;
    cin >> N;
    while (N--) {
        int a;
        cin >> a;
        if (a < 50) n0++;
        if (a > 50) n1++;
    }
    cout << (n1 ? (int)((__int128(1) << (n0 + n1 - 1)) % 1000000007): 0) << '\n';
}