#include <bits/stdc++.h>

using namespace std;

#define LL long long

LL pows(long long x,long long n)
{
    LL res=1;
    while(n)
    {
        if(n&1)
            res*=x;
        n>>=1;
        x*=x;
    }
    return res;
}

int main()
{
    LL n,m;
    double k;
    while(~scanf("%I64d%I64d%I64d",&m,&n,&k))
    {

        LL x=__gcd(m,(m + n*pows(2,k)));
        printf("%I64d/%I64d\n",m/x,(m + n*pows(2,k))/x);
    }
}