#include <bits/stdc++.h>
using namespace std;
const long long mod = 1e9 + 7;
long long my_pow(long long a, long long n) {
  if (n == 0) return 1;
  long long x = my_pow(a, n / 2);
  x = x * x % mod;
  if (n % 2) x = x * a % mod;
  return x;
}
long long gcd(long long a, long long b, long long& x, long long& y) {
  if (b == 0) {
    x = 1;
    y = 0;
    return a;
  } else {
    long long g = gcd(b, a % b, y, x);
    y -= x * (a / b);
    return g;
  }
}
long long inv(long long a) {
  long long x, y;
  gcd(a, mod, x, y);
  return (x + mod) % mod;
}
int main() {
  int n, even = 0;
  long long a = 2, b;
  scanf("%d", &n);
  for (int i = 0; i < n; i++) {
    scanf("%I64d", &b);
    if (b % 2 == 0) even = 1;
    a = my_pow(a, b);
  }
  a = a * inv(2) % mod;
  if (even) {
    b = a + 1;
  } else {
    b = a + mod - 1;
  }
  b = b * inv(3) % mod;
  cout << b << "/" << a << endl;
  return 0;
}
