#include<bits/stdc++.h>
#include<atcoder/modint>

int main(){
    using namespace std;
    using modint = atcoder::static_modint<1000000007>;
    unsigned long N;
    cin >> N;
    modint alice{}, bob{1};
    for(unsigned long i{}, p; i < N; ++i){
        cin >> p;
        if(p < 50){
            alice *= 2;
            bob *= 2;
        }else if(p > 50)bob = (alice += bob);
    }
    cout << alice.val() << endl;
    return 0;
}