#include <iostream>

/*
歯車の問題(1)

2
20 40

Z1 * theta1 = Z2 * theta2 => Z1 : Z2 = theta2 : theta1

theta2 = theta1 * (Z1 / Z2)

gr = theta1 / theta2 = Z2 / Z1

3
20 40 80
1  2  3

theta2 = theta1 * (20 / 40) = 0.5 * theta1
theta3 = theta2 * (40 / 80) = 0.5 * theta2

theta3 = 0.5 * 0.5 * theta1

theta1 / theta3 = 1 / (0.5 * 0.5)
*/

class FRACTION
{
	public:
	
	int numerator, denominator;
	
	FRACTION operator*(FRACTION frac)
	{
		FRACTION answer;
		
		answer.numerator = numerator * frac.numerator;
		answer.denominator = denominator * frac.denominator;
		
		return answer;
	}
};

FRACTION getGR(int N1, int N2)
{
	FRACTION GR;
	
	GR.numerator = N2;
	GR.denominator = N1;

	return GR;
}

int main(void)
{
	FRACTION GR;
	GR.numerator = 1;
	GR.denominator = 1;

	int N;

	std::cin >> N;
	
	int Z[N];
	
	for(int i = 0; i < N; i ++)
	{
		std::cin >> Z[i];
	}
	
	for(int i = 0; i < N - 1; i ++)
	{
		GR = GR * getGR(Z[i], Z[i + 1]);
	}
	
	std::cout << GR.numerator << "/" << GR.denominator << std::endl;
	
	return 0;
}