#include <bits/stdc++.h>
using namespace std;
long long MOD1 = 1000000007;
long long MOD2 = 3000000021;
long long order = 1000000006;
int main() {
  long long curPower = 1;
  long long k, temp;
  cin >> k;
  for (long long i = 0; i < k; i++) {
    cin >> temp;
    temp = temp % order;
    curPower *= temp;
    curPower = curPower % order;
  }
  curPower--;
  curPower += order;
  long x, y;
  x = curPower / 20001;
  y = curPower % 20001;
  long long ansD = 1;
  for (int i = 0; i < x; i++) {
    ansD *= 228857753;
    ansD = ansD % MOD2;
  }
  for (int i = 0; i < y; i++) {
    ansD *= 2;
    ansD = ansD % MOD2;
  }
  if (ansD % 3 == 1) {
    cout << ((ansD - 1) / 3) % MOD1;
  } else {
    cout << ((ansD + 1) / 3) % MOD1;
  }
  cout << '/';
  cout << (ansD % MOD1);
  cout << endl;
}
