#include <bits/stdc++.h>
int dr[] = {2, 2, -2, -2, 1, -1, 1, -1};
int dc[] = {1, -1, 1, -1, 2, 2, -2, -2};
int dr1[] = {0, 0, 1, 1, 1, -1, -1, -1};
int dc1[] = {1, -1, 1, 0, -1, 0, 1, -1};
int dr2[] = {0, 0, 1, -1};
int dc2[] = {1, -1, 0, 0};
using namespace std;
long long a[100005];
long long bigmod(long long n, long long p) {
  if (p == 0) return 1;
  long long x = bigmod(n, p / 2);
  x = (x * x) % 1000000007;
  if (p % 2 == 1) x = (x * n) % 1000000007;
  return x;
}
int main() {
  long long n, i, j;
  while (cin >> n) {
    bool f = 0;
    for (i = 1; i <= n; i++) {
      cin >> a[i];
      if (a[i] % 2 == 0) f = 1;
    }
    if (f == 1) {
      long long m = 2;
      for (i = 1; i <= n; i++) {
        m = bigmod(m, a[i]);
      }
      m = m * bigmod(2LL, 1000000007 - 2);
      m %= 1000000007;
      long long m1 = m;
      m1 = (m1 + 1) % 1000000007;
      m1 = m1 * bigmod(3LL, 1000000007 - 2);
      m1 %= 1000000007;
      cout << m1 << "/" << m << endl;
    } else {
      long long m = 2;
      for (i = 1; i <= n; i++) {
        m = bigmod(m, a[i]);
      }
      m = m * bigmod(2LL, 1000000007 - 2);
      m %= 1000000007;
      long long m1 = m;
      m1 = (m1 - 1 + 1000000007) % 1000000007;
      m1 = m1 * bigmod(3LL, 1000000007 - 2);
      m1 %= 1000000007;
      cout << m1 << "/" << m << endl;
    }
  }
  return 0;
}
