#include <bits/stdc++.h>
using namespace std;
const int inf = 0x3f3f3f3f;
const double eps = 1e-8;
const int mod = 1000000007;
const double pi = acos(-1);
inline void gn(long long& x) {
  int sg = 1;
  char c;
  while (((c = getchar()) < '0' || c > '9') && c != '-')
    ;
  c == '-' ? (sg = -1, x = 0) : (x = c - '0');
  while ((c = getchar()) >= '0' && c <= '9') x = x * 10 + c - '0';
  x *= sg;
}
inline void gn(int& x) {
  long long t;
  gn(t);
  x = t;
}
inline void gn(unsigned long long& x) {
  long long t;
  gn(t);
  x = t;
}
long long gcd(long long a, long long b) { return a ? gcd(b % a, a) : b; }
long long powmod(long long a, long long x, long long mod) {
  long long t = 1ll;
  while (x) {
    if (x & 1) t = t * a % mod;
    a = a * a % mod;
    x >>= 1;
  }
  return t;
}
int main() {
  int k;
  long long t;
  long long ex = 2;
  bool even = false;
  gn(k);
  for (int i = (1); i <= (k); i++) {
    gn(t);
    if (t % 2 == 0) even = true;
    ex = powmod(ex, t, mod);
  }
  long long q = ex * powmod(2, mod - 2, mod) % mod;
  long long p = q;
  if (even)
    p++;
  else
    p--;
  if (p < 0) p += mod;
  p = p * powmod(3, mod - 2, mod) % mod;
  printf("%I64d/%I64d\n", p, q);
  return 0;
}
