#include <bits/stdc++.h>
using namespace std;
const int p = 1e9 + 7, K = 100010;
long long read() {
  long long x = 0;
  int f = 1;
  char ch = getchar();
  while (!isdigit(ch)) {
    if (ch == '-') f = -1;
    ch = getchar();
  }
  while (isdigit(ch)) x = (x << 1) + (x << 3) + (ch ^ 48), ch = getchar();
  return x * f;
}
void print(long long x) {
  if (x < 0) {
    putchar('-');
    print(-x);
    return;
  }
  char ch = x % 10 + '0';
  if (x < 10) {
    putchar(ch);
    return;
  }
  print(x / 10);
  putchar(ch);
}
long long a;
long long pp, q;
int k;
bool fl;
long long qpow(long long x, long long y) {
  x %= p;
  long long ans = 1;
  while (y) {
    if (y & 1) ans = ans * x % p;
    x = x * x % p;
    y >>= 1;
  }
  return ans;
}
int main() {
  k = read();
  pp = 2;
  for (int i = 1; i <= k; i++) {
    a = read();
    if (!(a & 1)) fl = true;
    pp = qpow(pp, a);
    if (!a) {
      printf("1/1");
      return 0;
    }
  }
  pp = pp * qpow(2, p - 2) % p;
  q = pp;
  if (fl)
    pp++;
  else
    pp--;
  pp = pp * 333333336 % p;
  print(pp);
  putchar('/');
  print(q);
  return 0;
}
