#include <iostream>
#include <vector>
#include <algorithm>
#include <atcoder/modint>
using namespace std;
using i32 = int32_t;
using u32 = uint32_t;
using i64 = int64_t;
using u64 = uint64_t;
#define rep(i,n) for(int i=0; i<(n); i++)

using m32 = atcoder::modint1000000007;

int main(){
  int N; cin >> N;
  vector<int> A(N); rep(i,N) cin >> A[i];
  int l = 0;
  int r = 0;
  for(int a : A){
    if(a < 50) l++;
    if(a > 50) r++;
  }
  m32 t = m32(2).pow(l);
  if(r <= 0){ cout << "0\n"; return 0; }
  m32 ans = m32(2).pow(r-1);
  ans *= t;
  cout << ans.val() << endl;
  return 0;
}




struct ios_do_not_sync {
    ios_do_not_sync() {
        ios::sync_with_stdio(false);
        cin.tie(nullptr);
    }
} ios_do_not_sync_instance;