#include <bits/stdc++.h>
using namespace std;
int K, f;
long long x, ans = 2;
long long Fast(long long a, long long p) {
  long long res = 1, base = a;
  while (p) {
    if ((p & 1) == 1) res = (res * base) % 1000000007;
    base = (base * base) % 1000000007;
    p >>= 1;
  }
  return res;
}
int main() {
  cin >> K;
  for (int i = 1; i <= K; i++) {
    scanf("%lld", &x);
    ans = Fast(ans, x);
    if (x % 2 == 0) f = 1;
  }
  ans = (ans * Fast(2, 1000000007 - 2)) % 1000000007;
  if (f == 1)
    printf("%lld/%lld\n",
           (ans + 1) % 1000000007 * Fast(3, 1000000007 - 2) % 1000000007,
           ans % 1000000007);
  else
    printf("%lld/%lld\n",
           (ans - 1 + 1000000007) % 1000000007 * Fast(3, 1000000007 - 2) %
               1000000007,
           ans % 1000000007);
  return 0;
}
