#include <bits/stdc++.h>
using namespace std;
const long long mod = 1e9 + 7;
long long n, x, y = 2;
bool flag;
inline long long read() {
  long long x = 0, f = 1;
  char ch = getchar();
  while (!isdigit(ch)) {
    if (ch == '-') f = -1;
    ch = getchar();
  }
  while (isdigit(ch)) {
    x = x * 10 + (ch ^ 48);
    ch = getchar();
  }
  return x * f;
}
long long fpow(long long x, long long y) {
  long long res = 1, base = x;
  while (y) {
    if (y & 1) res = res * base % mod;
    base = base * base % mod;
    y >>= 1;
  }
  return res;
}
signed main() {
  n = read();
  for (long long i = 1; i <= n; i++)
    x = read(), flag = x % 2 ? flag : 1, y = fpow(y, x);
  y = y * fpow(2, mod - 2) % mod;
  if (flag)
    printf("%lld/%lld", (y + 1) * fpow(3, mod - 2) % mod, y);
  else
    printf("%lld/%lld", (y - 1 + mod) * fpow(3, mod - 2) % mod, y);
  return 0;
}
