#include <bits/stdc++.h>
using namespace std;
const long long N = 100005, P = 1e9 + 7;
long long a[N];
long long kpow(long long x, long long y) {
  long long res = 1;
  while (y) {
    if (y & 1) res = res * x % P;
    x = x * x % P, y >>= 1;
  }
  return res;
}
long long inv(long long x) { return kpow(x, P - 2); }
int main() {
  long long k;
  scanf("%lld", &k);
  bool flag = 0;
  long long dwn = 2;
  for (long long i = 1; i <= k; i++) {
    scanf("%lld", &a[i]);
    if (a[i] % 2 == 0) flag = 1;
    dwn = kpow(dwn, a[i]);
  }
  dwn = dwn * inv(2) % P;
  long long up;
  if (flag)
    up = (dwn + 1) * inv(3) % P;
  else
    up = (dwn - 1 + P) * inv(3) % P;
  printf("%lld/%lld\n", up, dwn);
  return 0;
}
