#include <bits/stdc++.h>
using namespace std;
const int MOD = 1e9 + 7;
const int MOD2 = MOD - 1;
int binpow(int x, int y) {
  int res = 1;
  while (y) {
    if (y % 2 == 1) res = (res * 1ll * x) % MOD;
    x = (x * 1ll * x) % MOD;
    y /= 2;
  }
  return res;
}
int main() {
  ios_base::sync_with_stdio(0);
  int k;
  cin >> k;
  int n = 1;
  for (int i = 0; i < k; i++) {
    long long t;
    cin >> t;
    t %= MOD2;
    n = (t * n) % MOD2;
  }
  n = (n + MOD2 - 1) % MOD2;
  int dwn = binpow(2, n);
  int up = dwn;
  if (n % 2 == 1)
    up = (up + 1) % MOD;
  else
    up = (up + MOD - 1) % MOD;
  up = (up * 1ll * binpow(3, MOD - 2)) % MOD;
  cout << up << "/" << dwn << endl;
  return 0;
}
