#include <bits/stdc++.h>
using namespace std;
#pragma comment(linker, "/STACK:102400000,102400000")
long long a[(100000 + 10)];
long long qpow(long long x, long long y) {
  long long ret = 1;
  while (y) {
    if (y & 1) ret = ret * x % 1000000007;
    x = x * x % 1000000007;
    y >>= 1;
  }
  return ret;
}
int main() {
  int n;
  scanf("%d", &n);
  bool e = 0;
  bool one = 1;
  for (int i = 0; i < n; ++i) {
    cin >> a[i];
    if ((a[i] & 1) == 0) e = 1;
    if (a[i] != 1) one = 0;
  }
  long long ans = 2;
  for (int i = 0; i < n; ++i) {
    ans = qpow(ans, a[i]);
  }
  ans = ans * qpow(2, 1000000007 - 2) % 1000000007;
  if (e) {
    long long p = (ans + 1) * qpow(3, 1000000007 - 2) % 1000000007;
    cout << p << "/" << ans << endl;
  } else {
    if (one)
      puts("0/1");
    else {
      long long p = (ans - 1 + 1000000007) % 1000000007 *
                    qpow(3, 1000000007 - 2) % 1000000007;
      cout << p << '/' << ans << endl;
    }
  }
}
