#include <bits/stdc++.h>
using namespace std;
long long a,b,c,d,tu,mau;
//chuongtrinhcon
long long ucln(long long a,long long b)
{
long long uocchunglonnhat;
if (a>b) swap(a,b);
for (long long i=a; i>=1; i--)
if ((a%i==0) and (b%i==0))
{
uocchunglonnhat=i;
break;
}
return(uocchunglonnhat);
}
//chuongtrinhchinh
int main()
{
cin>>a>>b>>c>>d;
tu=a*d+b*c;
mau=b*d;
cout<<tu/ucln(tu,mau)<<"/"<<mau/ucln(tu,mau);
return 0;
}