#include <bits/stdc++.h>
using namespace std;
pair<pair<long long, long long>, pair<long long, long long> > multiply(
    pair<pair<long long, long long>, pair<long long, long long> > m1,
    pair<pair<long long, long long>, pair<long long, long long> > m2) {
  pair<pair<long long, long long>, pair<long long, long long> > m3;
  m3.first.first = (m1.first.first * m2.first.first % 1000000007 +
                    m1.first.second * m2.second.first % 1000000007) %
                   1000000007;
  m3.first.second = (m1.first.first * m2.first.second % 1000000007 +
                     m1.first.second * m2.second.second % 1000000007) %
                    1000000007;
  m3.second.first = (m1.second.first * m2.first.first % 1000000007 +
                     m1.second.second * m2.second.first % 1000000007) %
                    1000000007;
  m3.second.second = (m1.second.first * m2.first.second % 1000000007 +
                      m1.second.second * m2.second.second % 1000000007) %
                     1000000007;
  return m3;
}
pair<pair<long long, long long>, pair<long long, long long> > binMatrix(
    pair<pair<long long, long long>, pair<long long, long long> > x,
    long long y) {
  if (y == 0) return {{1, 0}, {0, 1}};
  if (y == 1) return x;
  pair<pair<long long, long long>, pair<long long, long long> > q =
      binMatrix(x, y / 2);
  q = multiply(q, q);
  q = multiply(q, binMatrix(x, y % 2));
  return q;
}
long long binpow(long long a, long long b) {
  a %= 1000000007;
  b %= 1000000007 - 1;
  long long res = 1;
  while (b > 0) {
    if (b & 1) res = res * a % 1000000007;
    a = a * a % 1000000007;
    b >>= 1;
  }
  return res;
}
int main() {
  cin.tie(0)->sync_with_stdio(0);
  int k;
  cin >> k;
  long long ans = 1;
  for (int i = 0; i < k; i++) {
    long long x;
    cin >> x;
    x %= 1000000007 - 1;
    ans *= x;
    ans %= 1000000007 - 1;
  }
  if (ans == 0) {
    ans = 1000000007 - 1;
  }
  if (ans == 1) {
    cout << "0/1\n";
    return 0;
  }
  pair<pair<long long, long long>, pair<long long, long long> > po = {{1, 2},
                                                                      {1, 0}};
  po = binMatrix(po, ans - 2);
  long long y = po.first.first;
  long long inv1 = binpow(2, ans - 1);
  cout << y << "/" << inv1 << "\n";
}
