Little Petya likes numbers a lot. He found that number 123 in base 16 consists of two digits: the first is 7 and the second is 11. So the sum of digits of 123 in base 16 is equal to 18.

Now he wonders what is an average value of sum of digits of the number A written in all bases from 2 to A - 1.

Note that all computations should be done in base 10. You should find the result as an irreducible fraction, written in base 10.

Input

Input contains one integer number A (3 ≤ A ≤ 1000).

Output

Output should contain required average value in format «X/Y», where X is the numerator and Y is the denominator.

Examples

Input

5


Output

7/3


Input

3


Output

2/1

Note

In the first sample number 5 written in all bases from 2 to 4 looks so: 101, 12, 11. Sums of digits are 2, 3 and 2, respectively.
import static java.lang.Math.*;
import java.util.*;
import java.io.*;

public class _13_A {

    boolean showDebug = true;
    
    public void solve() throws Exception {
        
        int n = nextInt();
        int cnt = 0;
        for (int i=2; i<n; i++) cnt+=digitSum(n,i);
        println(cnt/gcd(cnt,n-2)+"/"+(n-2)/gcd(cnt,n-2));
    }
    
    int digitSum(long i, int base) {
        i = abs(i);
        int r = 0;
        while (i>0) {
            r+=i%base;
            i/=base;
        }
        return r;
    }

    ////////////////////////////////////////////////////////////////////////////    

    double EPS = 1e-7;
    int INF = Integer.MAX_VALUE;
    long INFL = Long.MAX_VALUE;
    double INFD = Double.MAX_VALUE;

    int[] dx = {0,1,0,-1};
    int[] dy = {-1,0,1,0};
    int[] dx8 = {0,1,1,1,0,-1,-1,-1};
    int[] dy8 = {-1,-1,0,1,1,1,0,-1};
    int[] knightMovesX = {1,2,2,1,-1,-2,-2,-1};
    int[] knightMovesY = {-2,-1,1,2,2,1,-1,-2};


    @SuppressWarnings("serial")
    class IncMap extends HashMap<Object, Integer> {
        boolean add(Object key, int amount) {
            Integer i = get(key);
            if (i!=null) {
                put(key, i+amount);
                return false;
            } else {
                put(key, amount);
                return true;
            }
        }
        boolean add(Object key) {
            return add(key, 1);
        }
    }
    

    int min(int... nums) {
        int r = INF;
        for (int i: nums)
            if (i<r) r=i;
        return r;
    }
    int max(int... nums) {
        int r = -INF;
        for (int i: nums)
            if (i>r) r=i;
        return r;
    }
    long minL(long... nums) {
        long r = INFL;
        for (long i: nums)
            if (i<r) r=i;
        return r;
    }
    long maxL(long... nums) {
        long r = -INFL;
        for (long i: nums)
            if (i>r) r=i;
        return r;
    }
    double minD(double... nums) {
        double r = INFD;
        for (double i: nums)
            if (i<r) r=i;
        return r;
    }
    double maxD(double... nums) {
        double r = -INFD;
        for (double i: nums)
            if (i>r) r=i;
        return r;
    }
    long sumArr(int[] arr) {
        long res = 0;
        for (int i: arr)
            res+=i;
        return res;
    }
    long sumArr(long[] arr) {
        long res = 0;
        for (long i: arr)
            res+=i;
        return res;
    }
    double sumArr(double[] arr) {
        double res = 0;
        for (double i: arr)
            res+=i;
        return res;
    }
    
    
    long partsFitCnt(long partSize, long wholeSize) {
        return (partSize+wholeSize-1)/partSize;
    }
    
    boolean odd(long i) {
        return (i&1)==1;
    }
    
    
    long digitProd(long i) {
        if (i==0) return 0;
        i = abs(i);
        long r = 1;
        while (i>0) {
            r*=i%10;
            i/=10;
        }
        return r;
    }
    
    long gcd (long a, long b) {
        while (b>0) {
            a%=b;
            long tmp=a; a=b; b=tmp;
        }
        return a;
    }
    long lcm(long a, long b) {
        return (a*b)/gcd(a,b);
    }
    
    double log_2 = log(2);
    double log2(double i) {
        if (i<=0) return -INFD;
        return log(i)/log_2;
    }
    long binpow(int x, int n) {
        long r = 1;
        while (n>0) {
            if ((n&1)!=0) r*=x;
            x*=x;
            n>>=1;
        }
        return r;
    }
    long fac(int i) {
        if (i>20) throw new IllegalArgumentException();
        return i<=1 ?  1:fac(i-1)*i;
    }
    
    
    double dist(double x, double y, double xx, double yy) {
        return sqrt((xx-x)*(xx-x)+(yy-y)*(yy-y));
    }
    
    
    boolean isPalindrome(String s) {
        for (int i=0; i<s.length()/2; i++)
            if (s.charAt(i)!=s.charAt(s.length()-1-i)) return false;
        return true;
    }
    int occurenciesCnt(String s, String pattern) {
        int res = 0;
        for (int i=0; i<s.length()-pattern.length()+1; i++)
            if (s.substring(i, i+pattern.length()).equals(pattern)) res++;
        return res;
    }
    int occurenciesCnt(String s, char pattern) {
        int res = 0;
        for (int i=0; i<s.length(); i++)
            if (s.charAt(i)==pattern) res++;
        return res;
    }
    
    
    int[] months = {0,31,28,31,30,31,30,31,31,30,31,30,31};
    boolean isLeapYear(int y) {
        return y%4==0 && (y%400==0 || y%100!=0);
    }
    boolean isValidDate(int d, int m, int y) {
        if (isLeapYear(y) && m==2 && d==29) return true;
        return m>0 && m<=12 && d>0 && d<=months[d];
    }
    int[] nextDay(int d, int m, int y) {
        if (d>=months[m])
            if (m==2 && d==28 && isLeapYear(y)) d++;
            else {d=1; m++;}
        else
            d++;
        if (m==13) {d=1; m=1; y++;}
        return new int[] {d,m,y};
    }
    
    String str(Object o) {
        return o.toString();
    }


    long timer = System.currentTimeMillis();
    void startTimer() {
        timer = System.currentTimeMillis();
    }
    void stopTimer() {
        System.err.println("time: "+(System.currentTimeMillis()-timer)/1000.0);
    }


    static BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
    static BufferedWriter out = new BufferedWriter(new OutputStreamWriter(System.out));

    String nextLine() throws IOException {
        return in.readLine();
    }
    String nextWord() throws IOException {
        StringBuilder sb = new StringBuilder();
        int c = 0;
        while (c<=' ') c=in.read();
        while (c>' ') {
            sb.append((char)c);
            c = in.read();
        }
        return sb.toString();
    }
    int nextInt() throws NumberFormatException, IOException {
        return Integer.parseInt(nextWord());
    }
    long nextLong() throws NumberFormatException, IOException {
        return Long.parseLong(nextWord());
    }
    double nextDouble() throws NumberFormatException, IOException {
        return Double.parseDouble(nextWord());
    }
    int[] nextArr(int size) throws NumberFormatException, IOException {
        int[] arr = new int[size];
        for (int i=0; i<size; i++)
            arr[i] = nextInt();
        return arr;
    }
    long[] nextArrL(int size) throws NumberFormatException, IOException {
        long[] arr = new long[size];
        for (int i=0; i<size; i++)
            arr[i] = nextLong();
        return arr;
    }
    double[] nextArrD(int size) throws NumberFormatException, IOException {
        double[] arr = new double[size];
        for (int i=0; i<size; i++)
            arr[i] = nextDouble();
        return arr;
    }
    String[] nextArrS(int size) throws NumberFormatException, IOException {
        String[] arr = new String[size];
        for (int i=0; i<size; i++)
            arr[i] = nextWord();
        return arr;
    }

    void print(Object o) throws IOException {
        out.write(o.toString());
    }
    void println(Object o) throws IOException {
        out.write(o.toString());
        out.newLine();
    }
    void print(Object... o) throws IOException {
        for (int i=0; i<o.length; i++) {
            if (i!=0) out.write(' ');
            out.write(o[i].toString());
        }
    }
    void println(Object... o) throws IOException {
        print(o);
        out.newLine();
    }
    void printArr(int[] arr) throws IOException {
        for (int i=0; i<arr.length; i++) {
            if (i!=0) out.write(' ');
            out.write(Integer.toString(arr[i]));
        }
    }
    void printArr(long[] arr) throws IOException {
        for (int i=0; i<arr.length; i++) {
            if (i!=0) out.write(' ');
            out.write(Long.toString(arr[i]));
        }
    }
    void printArr(double[] arr) throws IOException {
        for (int i=0; i<arr.length; i++) {
            if (i!=0) out.write(' ');
            out.write(Double.toString(arr[i]));
        }
    }
    void printArr(String[] arr) throws IOException {
        for (int i=0; i<arr.length; i++) {
            if (i!=0) out.write(' ');
            out.write(arr[i]);
        }
    }
    void printlnArr(int[] arr) throws IOException {
        printArr(arr);
        out.newLine();
    }
    void printlnArr(long[] arr) throws IOException {
        printArr(arr);
        out.newLine();
    }
    void printlnArr(double[] arr) throws IOException {
        printArr(arr);
        out.newLine();
    }
    void printlnArr(String[] arr) throws IOException {
        printArr(arr);
        out.newLine();
    }

    void debug(Object... o) {
        if (showDebug) System.err.println(Arrays.deepToString(o));
    }
     

    public static void main(String[] args) throws Exception {
        Locale.setDefault(Locale.US);
        new _13_A().solve();
        out.flush();
        out.close(); in.close();
    }
}
