#include <bits/stdc++.h>
using namespace std;
const long long mod = 1e9 + 7;
const long long ni2 = (mod + 1) / 2;
long long pp(long long a, long long b) {
  if (!b) return 1;
  long long cnt = pp(a, b / 2);
  cnt = cnt * cnt % mod;
  if (b & 1) cnt = cnt * a % mod;
  return cnt;
}
int main() {
  long long a, tmp = 2;
  long long ni3 = pp(3ll, mod - 2);
  int k;
  scanf("%d", &k);
  bool tag = 0;
  for (int i = 1; i <= k; ++i) {
    scanf("%I64d", &a);
    if (a % 2 == 0) tag = 1;
    a %= mod - 1;
    tmp = pp(tmp, a) % mod;
  }
  tmp = tmp * ni2 % mod;
  if (tag) {
    long long cur = (tmp + 1) % mod * ni3 % mod;
    printf("%d/%d\n", (int)cur, (int)tmp);
  } else {
    long long cur = (tmp - 1) % mod * ni3 % mod;
    cur = (cur % mod + mod) % mod;
    printf("%d/%d\n", (int)cur, (int)tmp);
  }
  return 0;
}
