#include <bits/stdc++.h>
long long fpow(long long x, long long y, long long mod) {
  long long s = 1, base = x;
  while (y) {
    if (y & 1) s = s * base % mod;
    base = base * base % mod;
    y >>= 1;
  }
  return s;
}
const int inv3 = 333333336;
const int inv2 = 500000004;
const int mod = 1000000007;
const int maxn = 1000000;
int main() {
  long long t;
  int n, m = 1;
  scanf("%d", &n);
  bool flag = false;
  for (int i = 0; i < n; i++) {
    scanf("%lld", &t);
    m = (m * (t % (mod - 1))) % (mod - 1);
    if (!(t % 2)) flag = true;
  }
  long long p = 2, q = 2;
  q = fpow(2, m, mod);
  q = (q * inv2) % mod;
  p = (q + (flag ? 1 : -1)) % mod;
  p = p * inv3 % mod;
  printf("%lld/%lld\n", p, q);
  return 0;
}
