#include <bits/stdc++.h>
using namespace std;
inline long long lin() {
  long long x;
  scanf("%lld", &x);
  return x;
}
int k = 0;
const int N = 1e5 + 100, Mod = 1e9 + 7;
long long a;
int powm(int x, long long p) {
  int ans = 1;
  while (p) {
    if (p & 1) ans = 1ll * ans * x % Mod;
    x = 1ll * x * x % Mod;
    p >>= 1;
  }
  return ans;
}
int ok(int x) {
  x += Mod;
  x %= Mod;
  return x;
}
int main() {
  scanf("%d", &k);
  int pn = 2;
  bool iseven = false;
  for (int i = 0; i < k; i++) {
    a = lin();
    pn = powm(pn, a);
    iseven |= (a % 2 == 0);
  }
  int pn_1 = 1ll * pn * powm(2, Mod - 2) % Mod;
  if (iseven) {
    cout << (1ll * ok(pn_1 - 2) * powm(3, Mod - 2) + 1) % Mod << '/' << pn_1;
  } else {
    cout << 1ll * ok(pn_1 - 1) * powm(3, Mod - 2) % Mod << '/' << pn_1;
  }
}
