#include <bits/stdc++.h>
using namespace std;
const int N = 1e5 + 5;
const long long MOD = 1e9 + 7;
long long a[N];
long long mypow(long long a, long long b) {
  long long res = 1;
  while (b) {
    if (b & 1) {
      res = (res * a) % MOD;
    }
    a = (a * a) % MOD;
    b >>= 1;
  }
  return res;
}
int main() {
  int n, i;
  bool bEven = false;
  long long p, q;
  scanf("%d", &n);
  for (p = 2, q = 2, i = 0; i < n; i++) {
    scanf(
        "%l"
        "ld",
        &a[i]);
    if (!(a[i] & 1)) {
      bEven = true;
    }
    p = mypow(p, a[i]);
  }
  p = p * mypow(2, MOD - 2) % MOD;
  q = p;
  if (bEven) {
    p = (p + 1) % MOD;
  } else {
    p = (p + MOD - 1) % MOD;
  }
  p = p * mypow(3, MOD - 2) % MOD;
  printf("%lld/%lld\n", p, q);
  return 0;
}
