#include <bits/stdc++.h>
using namespace std;
inline long long read() {
  register long long x = 0, f = 1;
  register char ch = getchar();
  while (ch < '0' || ch > '9') {
    if (ch == '-') f = -1;
    ch = getchar();
  }
  while (ch >= '0' && ch <= '9') {
    x = x * 10 + ch - '0';
    ch = getchar();
  }
  return x * f;
}
inline void write(long long x) {
  if (x < 0) x = -x, putchar('-');
  if (x > 9) write(x / 10);
  putchar(x % 10 + '0');
}
const long long N = 1e5, mod = 1e9 + 7;
long long k, n, up, down;
long long a[N];
long long ksm(long long b, long long p, long long k) {
  long long base = b, ans = 1;
  while (p) {
    if (p & 1) ans = (1LL * ans * base) % k;
    base = (1LL * base * base) % k;
    p /= 2;
  }
  return ans;
}
void Exgcd(long long a, long long b, long long &x, long long &y) {
  if (!b)
    x = 1, y = 0;
  else
    Exgcd(b, a % b, y, x), y -= a / b * x;
}
long long Qinv(long long a, long long p) {
  long long x, y;
  Exgcd(a, p, x, y);
  x = (x % p + p) % p;
  return x;
}
signed main() {
  k = read();
  n = 1;
  for (long long i = 1; i <= k; i++) {
    a[i] = read() % (mod - 1);
    n = (n * a[i]) % (mod - 1);
  }
  if (n == 0) n = mod - 1;
  down = ksm(2, n - 1, mod);
  up = 1LL * Qinv(3, mod) *
       (ksm(2, n - 1, mod) - ((n - 1) & 1 ? -1 : 1) + mod) % mod;
  cout << up << "/" << down;
  return 0;
}
