#include <bits/stdc++.h>
#pragma warning(disable : 4996)
using namespace std;
int IT_MAX = 1 << 21;
const int MOD = 1000000007;
const int INF = 1034567891;
const long long LL_INF = 1234567890123456789ll;
const double PI = 3.141592653589793238;
const long double ERR = 1E-12;
const long long mod = 1e9 + 7;
long long qpow(long long x, long long y) {
  if (y == 0) return 1;
  long long tmp = qpow(x, y / 2);
  if (y & 1) return tmp * tmp % mod * x % mod;
  return tmp * tmp % mod;
}
const int maxnode = 4;
struct Matrix {
  int n;
  long long maze[maxnode][maxnode];
  void init(int n) {
    this->n = n;
    memset(maze, 0, sizeof(maze));
  }
  Matrix operator*(Matrix &rhs) {
    Matrix m;
    m.init(n);
    for (int i = 0; i < n; i++)
      for (int j = 0; j < n; j++)
        for (int k = 0; k < n; k++)
          m.maze[i][j] = (m.maze[i][j] + maze[i][k] * rhs.maze[k][j]) % mod;
    return m;
  }
  void print() {
    for (int i = 0; i < n; i++) {
      for (int j = 0; j < n; j++) {
        cout << maze[i][j] << " ";
      }
      cout << endl;
    }
  }
};
Matrix qpow(Matrix a, long long n) {
  Matrix ans;
  ans.init(a.n);
  for (int i = 0; i < ans.n; i++) ans.maze[i][i] = 1;
  while (n) {
    if (n & 1) ans = ans * a;
    a = a * a;
    n >>= 1;
  }
  return ans;
}
int main() {
  int n;
  cin >> n;
  long long tmp = 2;
  long long flag = -1;
  for (int i = 0; i < n; i++) {
    long long ta;
    scanf("%I64d", &ta);
    if (ta % 2 == 0) flag = 1;
    tmp = qpow(tmp, ta);
  }
  long long ans = tmp * qpow(2, mod - 2) % mod;
  cout << (ans + mod + flag) % mod * qpow(3, mod - 2) % mod << "/" << ans;
}
