#include <bits/stdc++.h>
using namespace std;
const int mod = 1e9 + 7;
const int maxn = 1e5 + 50;
long long fast_mod(long long x, long long k) {
  long long res = 1;
  while (k) {
    if (k & 1) res = res * x % mod;
    k >>= 1, x = x * x % mod;
  }
  return res;
}
int n;
long long A[maxn];
long long x, y;
bool is_odd = 1;
int main() {
  scanf("%d", &n);
  y = 2;
  for (int i = 1; i <= n; i++) {
    scanf("%lld", &A[i]);
    if (A[i] % 2 == 0) is_odd = 0;
  }
  for (int i = 1; i <= n; i++) y = fast_mod(y, A[i]);
  y = y * fast_mod(2, mod - 2) % mod;
  if (is_odd) {
    long long res = y - 1;
    if (res < 0) res += mod;
    if (res >= mod) res -= mod;
    x = res * fast_mod(3, mod - 2) % mod;
  } else {
    long long res = y + 1;
    if (res < 0) res += mod;
    if (res >= mod) res -= mod;
    x = res * fast_mod(3, mod - 2) % mod;
  }
  printf("%lld/%lld\n", x, y);
  return 0;
}
