#include <iostream>

using namespace std;

long long nwd(long long a,long long b)
{
    long long c;
    while(b != 0)
    {
        c=a % b;
        a = b;
        b = c;
    }
    return a;
}

int main()
{
    long long n,a=1,b=2,c;
    cin>>n;
    for(long long i=2;i<=n;i++)
    {
        a=(a*(i*2))+(1*b);
        b=b*(i*2);
        c=nwd(a,b);
        a=a/c;
        b=b/c;
    }
    cout<<a<<"/"<<b;
    return 0;
}