#include <bits/stdc++.h>
using namespace std;
const long long pr = 1e9 + 7;
long long K, a, p, q;
long long quickpow(long long x, long long y) {
  long long ret = 1LL;
  for (; y; y >>= 1LL) {
    if (y & 1LL) {
      ret = ret * x;
      if (ret >= pr) ret %= pr;
    }
    x *= x;
    if (x >= pr) x %= pr;
  }
  return ret;
}
int main() {
  cin >> K;
  long long n = 1LL;
  for (int i = 0; i < K; i++) {
    cin >> a;
    a %= (pr - 1);
    n = n * a;
    if (n >= pr - 1) n %= (pr - 1);
  }
  if (n == 0) n = pr - 1;
  p = (quickpow(2LL, n - 1) + quickpow(-1LL, n) + pr) % pr;
  p = (p * quickpow(3LL, pr - 2)) % pr;
  q = quickpow(2LL, n - 1);
  cout << p << "/" << q << endl;
  return 0;
}
