#include <bits/stdc++.h>
using namespace std;
uint64_t C = 1000000007ull;
uint64_t binpow(uint64_t a, uint64_t n) {
  uint64_t res = 1;
  while (n) {
    if (n & 1) {
      res *= a;
      res %= C;
    }
    a *= a;
    a %= C;
    n >>= 1;
  }
  return res;
}
int main() {
  std::ios_base::sync_with_stdio(false);
  int k;
  cin >> k;
  uint64_t current = 2;
  int is_chet = -1;
  for (int i = 0; i < k; ++i) {
    uint64_t x;
    cin >> x;
    current = binpow(current, x);
    if (x % 2 == 0) {
      is_chet = 1;
    }
  }
  while (current % 2 != 0) {
    current += C;
  }
  current /= 2;
  auto x = (current + is_chet) % C;
  while (x % 3 != 0) {
    x += C;
  }
  x /= 3;
  x %= C;
  auto y = current;
  std::cout << x << "/" << y << "\n";
  return 0;
}
