#include <bits/stdc++.h>
using namespace std;
const int MOD = 1e9 + 7;
const int maxn = 100000 + 100;
long long aa[maxn];
long long quick_mod(long long t, long long n) {
  long long ans = 1;
  while (n) {
    if (n & 1) ans = ans * t % MOD;
    t = t * t % MOD;
    n >>= 1;
  }
  return ans;
}
long long Inv(long long x) { return quick_mod(x, MOD - 2); }
int main() {
  long long inv3 = Inv(3);
  long long inv2 = Inv(2);
  int n, f = 1, f2 = 0;
  scanf("%d", &n);
  for (int i = 1; i <= n; ++i) {
    scanf("%lld", &aa[i]);
    if (aa[i] % 2 == 0) f = 0;
    if (aa[i] > 1) f2 = 1;
  }
  if (!f2) {
    puts("0/1");
    return 0;
  }
  long long b = 1, a = 1;
  b = quick_mod(2, aa[1]);
  for (int i = 2; i <= n; ++i) {
    b = quick_mod(b, aa[i]);
  }
  b = b * inv2 % MOD;
  if (f) {
    a = ((b - 1 + MOD) * inv3 % MOD);
  } else {
    a = ((b - 2 + MOD) * inv3 % MOD + 1) % MOD;
  }
  printf("%lld/%lld\n", a, b);
  return 0;
}
