#include <bits/stdc++.h>
using namespace std;
long long int mul_inv(long long int n, long long int p, long long int m) {
  if (p == 1) {
    return n % m;
  } else if (p % 2 == 0) {
    long long int t = mul_inv(n, p / 2, m);
    return ((t) * (t)) % m;
  } else {
    long long int t = mul_inv(n, p / 2, m);
    return ((((n % m) * t) % m) * t) % m;
  }
}
int main() {
  long long k, a[100006], e = 0, p, q, i;
  scanf("%lld", &k);
  ;
  for (i = 0; i < k; i++) {
    scanf("%lld", &a[i]);
    ;
    if (!(a[i] % 2)) {
      e++;
    }
  }
  if (e) {
    p = 2;
    for (i = 0; i < k; i++) {
      p = mul_inv(p, a[i], 1000000007LL);
    }
    p = ((p) % 1000000007LL * (mul_inv(2, 1000000007LL - 2, 1000000007LL))) %
        1000000007LL;
    q = p;
    p = ((p + 1) % 1000000007LL *
         (mul_inv(3, 1000000007LL - 2, 1000000007LL))) %
        1000000007LL;
    cout << p << "/" << q;
  } else {
    p = 2;
    for (i = 0; i < k; i++) {
      p = mul_inv(p, a[i], 1000000007LL);
    }
    p = ((p) % 1000000007LL * (mul_inv(2, 1000000007LL - 2, 1000000007LL))) %
        1000000007LL;
    q = p;
    p = ((p - 1 + 3 * 1000000007LL) % 1000000007LL *
         (mul_inv(3, 1000000007LL - 2, 1000000007LL))) %
        1000000007LL;
    cout << p << "/" << q;
  }
}
