#include <bits/stdc++.h>
using namespace std;
const int mod = 1000000007;
struct Int {
  int v;
  Int() {}
  Int(int x) {
    v = x % mod;
    if (v < 0) v += mod;
  }
  Int(long long x) {
    v = x % mod;
    if (v < 0) v += mod;
  }
  inline Int operator+(const Int &b) const { return v + b.v; }
  inline Int operator-(const Int &b) const { return v - b.v; }
  inline Int operator-() const { return -v; }
  inline Int operator*(const Int &b) const { return (long long)v * b.v; }
  friend inline Int pw(Int a, long long b) {
    Int ans = 1;
    for (; b; b >>= 1, a = a * a)
      if (b & 1) ans = ans * a;
    return ans;
  }
};
int K;
int main() {
  Int inv2 = pw(Int(2), mod - 2);
  Int inv3 = pw(Int(3), mod - 2);
  scanf("%d", &K);
  Int t = 2;
  int is_even = 0;
  for (int i = 1; i <= K; i++) {
    long long a;
    scanf("%I64d", &a);
    t = pw(t, a);
    is_even |= (~a & 1);
  }
  Int p = (t * inv2 + (is_even ? 1 : -1)) * inv3;
  Int q = t * inv2;
  printf("%d/%d\n", p.v, q.v);
  return 0;
}
