#include <bits/stdc++.h>
using namespace std;
const int N = 100008, mod = 1e9 + 7;
int k, even;
long long n, p, q;
int power(int x, long long y, int mod) {
  int tmp = x, ret = 1;
  while (y) {
    if (y & 1) ret = (long long)ret * tmp % mod;
    tmp = (long long)tmp * tmp % mod;
    y >>= 1;
  }
  return ret;
}
long long inc(int x, int y) {
  x += y;
  if (x >= mod) x -= mod;
  if (x < 0) x += mod;
  return x;
}
int main() {
  scanf("%d", &k);
  n = 1;
  for (int i = 1; i <= k; i++) {
    long long x;
    scanf("%I64d", &x);
    if (x % 2 == 0) even = 1;
    x %= (mod - 1);
    n = n * x % (mod - 1);
  }
  n = n - 1;
  if (n < 0) n += (mod - 1);
  if (even == 0) even = -1;
  int tmp = power(2, n, 3);
  if ((tmp + even) % 3 == 0) {
    p = inc(power(2, n, mod), even) * power(3, mod - 2, mod) % mod;
    q = power(2, n, mod);
  } else {
    p = inc(power(2, n, mod), even);
    q = power(2, n, mod) * 3 % mod;
  }
  printf("%I64d/%I64d\n", p, q);
  return 0;
}
