#include <bits/stdc++.h>
#pragma GCC optimize "-O3"
using namespace std;
const long long MOD = 1e9 + 7;
long long pw(long long a, long long b) {
  long long ans = 1;
  while (b) {
    while (!(b & 1)) b >>= 1, a = (a * a) % MOD;
    ans = (ans * a) % MOD, --b;
  }
  return ans;
}
const int MAXN = 120000;
int k;
long long a[MAXN];
long long pw2(long long x) {
  long long ans = x;
  for (int i = 0; i < k; ++i) ans = pw(ans, a[i]);
  return ans;
}
int main() {
  ios_base::sync_with_stdio(false), cin.tie(0), cout.tie(0);
  cin >> k;
  for (int i = 0; i < k; ++i) cin >> a[i];
  long long p = pw2(2) * pw(2, MOD - 2) % MOD + pw2(MOD - 1);
  p %= MOD;
  p = p * pw(3, MOD - 2) % MOD;
  long long q = pw2(2) * pw(2, MOD - 2) % MOD;
  cout << p << "/" << q << "\n";
  return 0;
}
