/* -*- coding: utf-8 -*-
 *
 * 1682.cc:  No.1682 Unfair Game - yukicoder
 */

#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<iostream>
#include<string>
#include<vector>
#include<map>
#include<set>
#include<stack>
#include<list>
#include<queue>
#include<deque>
#include<algorithm>
#include<numeric>
#include<utility>
#include<complex>
#include<functional>
 
using namespace std;

/* constant */

const int MOD = 1000000007;

/* typedef */

typedef long long ll;

/* global variables */

/* subroutines */

int powmod(int a, int n) {  // a^n % MOD
  int pm = 1;
  while (n > 0) {
    if (n & 1) pm = (ll)pm * a % MOD;
    a = (ll)a * a % MOD;
    n >>= 1;
  }
  return pm;
}

/* main */

int main() {
  int n;
  scanf("%d", &n);

  int c0 = 0, c1 = 0;
  for (int i = 0; i < n; i++) {
    int pi;
    scanf("%d", &pi);

    if (pi < 50) c0++;
    else if (pi > 50) c1++;
  }

  if (c1 == 0) puts("0");
  else printf("%d\n", powmod(2, c0 + c1 - 1));

  return 0;
}