#include <iostream>
#include <string>
#include <vector>
#include <cmath>
#include <algorithm>
#include <cstdlib>
#include <ctime>
#include <cstdio>
#include <functional>
#include <set>
#include <sstream>
#include <map>
#include <queue>
#include <stack>
using namespace std;

long long gcd(long long x,long long y){
	return y==0?x:gcd(y,x%y);
}

int main(){

	int n;
	cin>>n;
	
	vector<long long> z(n);
	for(int i=0;i<n;i++) cin>>z[i];
		
	pair<long long,long long> ta(1,1);
	for(int i=1;i<n;i++){
		pair<long long,long long> tb(ta.first*z[i-1],ta.second*z[i]);
		long long d=gcd(tb.first,tb.second);
		tb.first/=d; tb.second/=d;
		ta=tb;
	}
	
	cout<<ta.second<<"/"<<ta.first<<endl;

}