#include <stdio.h>
#include <stdlib.h>

int main(){

	int N = 0;

	long int initgear = 0;
	long int currentgear = 0;
	long int beforegear = 0;
	long int lastgear = 0;

	char str[20];
	long int c = 0;

	gets(str);
	N = atoi(str);

	for(int i = 0; i < N; i++){

		int j = 0;

		while ((c = getchar()) != EOF){

			if(c == ' '){
				str[j] = '\0';
				break;
			}

			str[j] = c;
			j++;
		}

		currentgear = atoi(str);
		beforegear = currentgear;


		if(i == 0){
			initgear = currentgear;
		}
		if(i == N-1)
			lastgear = currentgear;

	}


	printf("%ld/%ld", lastgear, initgear);

	return 0;

}