Manao has a monitor. The screen of the monitor has horizontal to vertical length ratio a:b. Now he is going to watch a movie. The movie's frame has horizontal to vertical length ratio c:d. Manao adjusts the view in such a way that the movie preserves the original frame ratio, but also occupies as much space on the screen as possible and fits within it completely. Thus, he may have to zoom the movie in or out, but Manao will always change the frame proportionally in both dimensions.

Calculate the ratio of empty screen (the part of the screen not occupied by the movie) to the total screen size. Print the answer as an irreducible fraction p / q.

Input

A single line contains four space-separated integers a, b, c, d (1 ≤ a, b, c, d ≤ 1000).

Output

Print the answer to the problem as "p/q", where p is a non-negative integer, q is a positive integer and numbers p and q don't have a common divisor larger than 1.

Examples

Input

1 1 3 2


Output

1/3


Input

4 3 2 2


Output

1/4

Note

Sample 1. Manao's monitor has a square screen. The movie has 3:2 horizontal to vertical length ratio. Obviously, the movie occupies most of the screen if the width of the picture coincides with the width of the screen. In this case, only 2/3 of the monitor will project the movie in the horizontal dimension: <image>

Sample 2. This time the monitor's width is 4/3 times larger than its height and the movie's frame is square. In this case, the picture must take up the whole monitor in the vertical dimension and only 3/4 in the horizontal dimension: <image>
import java.io.*;
import java.util.*;


public class Main {
    static PrintWriter pw=new PrintWriter(System.out);
    public static void main(String[] args) throws IOException {
        //BufferedReader reader=new BufferedReader(new FileReader("input.txt"));
        //PrintWriter pw=new PrintWriter(new BufferedWriter(new FileWriter("output.txt")));
        //BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
        //Scanner scanner=new Scanner(System.in);
        Reader scanner = new Reader();

        int x=scanner.nextInt(),y=scanner.nextInt();
        int a=scanner.nextInt(),b=scanner.nextInt();

        //System.out.println(x+" "+y+" "+a+" "+b);
        double xy=(double) x/y;
        double ab=(double) a/b;
        //System.out.println(xy+" "+ab);
        if (xy>ab)
            System.out.println(div(x,y,a,b));
        else if (xy==ab)
            System.out.println("0/1");
        else
            System.out.println(div(a,b,x,y));

















        pw.close();

    }
    static String div(int x,int y,int a,int b){
        int c=a*y;
        int d=b*x;
        c=d-c;
        int l=Math.min(c,d);
        for (int i = 2; i <=l ; i++) {
            while (c%i==0 && d%i==0){
                c/=i;
                d/=i;
            }
        }

        return c+"/"+d;

    }
    static boolean isInt(double n){
        if (n>10e8-1)return false;
        else return n == (long) n;
    }
    static long s(long n){
        String s=String.valueOf(n);
        long sum=0L;
        for (int i = 0; i <s.length() ; i++) {
            sum+=s.charAt(i)-48;
        }
        return sum;
    }
    static Vector<Integer> set=new Vector<>();
    static void com(int m2,int u2){
        if (u2>0){
            com(m2+1,u2-1);
            com(m2-1,u2-1);
        }
        else
            set.add(m2);

    }




    static int find(int n,int[] p){
        if (p[n]==n)return n;
        return p[n]=find(p[n],p);
    }
    static void union(int a,int b,int[] p){
        int aRoot=find(a,p);
        int bRoot=find(b,p);
        if (aRoot==bRoot)return;
        p[bRoot]=aRoot;
        //level[aRoot]+=level[bRoot];
    }
}
class node implements Comparable<node>{
    Integer no;
    Integer cost;
    Vector<node> adj=new Vector<>();
    public node(Integer no, Integer cost) {
        this.no = no;
        this.cost = cost;
    }

    @Override
    public String toString() {
        return "node{" +
                "no=" + no +
                ", cost=" + cost +
                '}';
    }

    @Override
    public int compareTo(node o) {
        return o.cost-this.cost;
    }
}
class edge implements Comparable<edge>{
    tuple u;
    Double cost;
    public edge(tuple u, Double cost) {
        this.u = u;
        this.cost = cost;
    }
    @Override
    public int compareTo(edge o) {
        return this.cost.compareTo(o.cost);
    }

    @Override
    public String toString() {
        return "edge{" +
                "u=" + u +
                ", cost=" + cost +
                '}';
    }
}
///*
class tuple implements Comparable<tuple>{
    double a;
    double b;
    tuple(double a, double b) {
        this.a = a;
        this.b = b;
    }

    @Override
    public int compareTo(tuple o) {
        return (int) (this.a-o.a);
    }
}

//*/
class Reader {
    final private int BUFFER_SIZE = 1 << 16;
    private DataInputStream din;
    private byte[] buffer;
    private int bufferPointer, bytesRead;

    public Reader() {
        din = new DataInputStream(System.in);
        buffer = new byte[BUFFER_SIZE];
        bufferPointer = bytesRead = 0;
    }

    public Reader(String file_name) throws IOException {
        din = new DataInputStream(new FileInputStream(file_name));
        buffer = new byte[BUFFER_SIZE];
        bufferPointer = bytesRead = 0;
    }

    public String readLine() throws IOException {
        byte[] buf = new byte[64];
        int cnt = 0, c;
        while ((c = read()) != -1) {
            if (c == '\n') break;
            buf[cnt++] = (byte) c;
        }
        return new String(buf, 0, cnt);
    }

    public int nextInt() throws IOException {
        int ret = 0;
        byte c = read();
        while (c <= ' ') c = read();
        boolean neg = (c == '-');
        if (neg) c = read();
        do {
            ret = ret * 10 + c - '0';
        } while ((c = read()) >= '0' && c <= '9');
        if (neg) return -ret;
        return ret;
    }

    public long nextLong() throws IOException {
        long ret = 0;
        byte c = read();
        while (c <= ' ') c = read();
        boolean neg = (c == '-');
        if (neg) c = read();
        do {
            ret = ret * 10 + c - '0';
        } while ((c = read()) >= '0' && c <= '9');
        if (neg) return -ret;
        return ret;
    }

    public double nextDouble() throws IOException {
        double ret = 0, div = 1;
        byte c = read();
        while (c <= ' ') c = read();
        boolean neg = (c == '-');
        if (neg) c = read();
        do {
            ret = ret * 10 + c - '0';
        } while ((c = read()) >= '0' && c <= '9');
        if (c == '.') while ((c = read()) >= '0' && c <= '9') ret += (c - '0') / (div *= 10);
        if (neg) return -ret;
        return ret;
    }

    private void fillBuffer() throws IOException {
        bytesRead = din.read(buffer, bufferPointer = 0, BUFFER_SIZE);
        if (bytesRead == -1) buffer[0] = -1;
    }

    private byte read() throws IOException {
        if (bufferPointer == bytesRead) fillBuffer();
        return buffer[bufferPointer++];
    }

    public void close() throws IOException {
        if (din == null) return;
        din.close();
    }
}