#include <bits/stdc++.h>
using namespace std;
const int Mod = 1e9 + 7;
int k;
bool pd = 0;
long long read() {
  long long ans = 0;
  char c = getchar();
  while (c < '0' || c > '9') c = getchar();
  while (c >= '0' && c <= '9') {
    ans = ans * 10 + c - 48;
    c = getchar();
  }
  return ans;
}
long long quick(long long x, long long y) {
  long long js = 0, ans = 1;
  for (long long i = 1; i <= y; i <<= 1) {
    if (i & y) ans = (ans * x) % Mod;
    x = (x * x) % Mod;
  }
  return ans;
}
int main() {
  scanf("%d", &k);
  long long ans = 2;
  for (int i = 1; i <= k; i++) {
    long long x = read();
    if (x % 2 == 0) pd = 1;
    ans = quick(ans, x) % Mod;
  }
  ans = (ans * quick(2, Mod - 2)) % Mod;
  long long ans1 = ans;
  if (pd)
    ans1 += 1;
  else
    ans1 -= 1;
  ans1 = (ans1 * quick(3, Mod - 2)) % Mod;
  printf("%I64d/%I64d\n", ans1, ans);
}
