#include <bits/stdc++.h>
using namespace std;
long long a,b,c,d,x,y;
bool ok;
int main(){
	cin >> a >> b >> c >> d;
	a *= d;
	c *= b;
	x = a + c;
	y = b * d;
	if(x < 0){
		ok = 1;
		x = -x;
	}
	for(long long i = 2;i <= min(x,y);i++){
		while(x %i == 0 &&y % i == 0){
			x /= i;
			y /= i;
		}
	}
	if(ok)cout << "-";
	if(x > y){
		cout << x / y;
		x %= y;
		if(x)printf("+%lld/%lld",x,y);
	}
	else if(x)printf("%lld/%lld",x,y);
	else cout << 0;
	return 0;
}