package yukicoder;
import java.util.Scanner;
public class Main{
	public static void main(String[] args){
		new Main().solve();
	}
	void solve(){
		Scanner sc=new Scanner(System.in);
		int n=sc.nextInt();
		long[] z=new long[n];
		for(int i=0;i<n;i++)z[i]=sc.nextLong();
		long gcd=gcd(z[0],z[n-1]);
		System.out.println(z[n-1]/gcd+"/"+z[0]/gcd);
		/*
		 *θ1 = z2/z1 * θ2
		 * 	 = z2/z1 * z3/2 * θ3
		 *   = z3/z1 * θ3
		 *...
		 *=zn/z1 * θn
		 *
		 *gr=θ1/θn=zn/z1
		 */
	}
	long lcm(long t1,long t2){
		long a=gcd(t1,t2);
		long tt1=t1/a;
		long tt2=t2/a;
		return tt1*tt2*a;
	}
	long gcd(long t1,long t2){
		if(t1<t2){
			long d=t2;
			t2=t1;
			t1=d;
		}
		if(t2==0)return t1;
		return gcd(t2,t1%t2);
	}
}