#include <bits/stdc++.h>
long long pow(long long p) {
  long long a = 2, ans = 1;
  while (p) {
    if (p & 1) ans *= a;
    ans %= 1000000007;
    a *= a;
    a %= 1000000007;
    p >>= 1;
  }
  return ans;
}
long long inv2, inv3;
int main() {
  inv2 = (1000000007 - 1000000007 / 2) % 1000000007;
  inv3 = (inv2 * (1000000007 - 1000000007 / 3)) % 1000000007;
  int k;
  scanf("%d", &k);
  long long p = 1;
  bool flag = false;
  while (k--) {
    long long a;
    scanf("%I64d", &a);
    if (a % 2 == 0) flag = true;
    a %= (1000000007 - 1);
    p *= a;
    p %= (1000000007 - 1);
  }
  long long pans = pow(p), fans;
  pans *= inv2;
  pans %= 1000000007;
  if (flag)
    fans = pans + 1;
  else
    fans = pans - 1;
  fans = (fans + 1000000007) % 1000000007;
  fans *= inv3;
  fans %= 1000000007;
  printf("%I64d/%I64d\n", fans, pans);
}
