牛客网PAT，java提交运行错误(甲组练习题1001题目)

public class Main {
 
    public static int gcd(int x, int y){
        if(y == 0)
            return x;
         else
            return gcd(y,x%y);
    }
     
    public static void main(String[] args) {
        // TODO Auto-generated method stub
 
        Scanner input = new Scanner(System.in);
        int i = input.nextInt();
        Scanner all = new Scanner(System.in);
        String str = all.nextLine();
        String[] arr = str.split(" ");
        int a1 = 0;
        int b1 = 0;
        int c1 = 1;
        for(int j = 0; j<arr.length;j++)
        {
             
            String[] arr1 = arr[j].split("/");
            int b = Integer.parseInt(arr1[0]);
            int c = Integer.parseInt(arr1[1]);
             
            b1 = b1*c + b*c1;
            c1 = c1*c;
             
            int gccd = gcd(b1,c1);
            b1 = b1/gccd;
            c1 = c1/gccd;
             
        }
         
        a1 = b1/c1;
        b1 = b1-c1*a1;
        if(a1==0)
        {
            System.out.println(0+" "+b1+"/"+c1);
        }
        else if(a1!=0 && b1==0)
        {
            System.out.println(a1);

        }

        else if(a1!=0 && b1!=0)
        {
            System.out.println(a1+" "+b1+"/"+c1);
        }
        else
        {
            System.out.println(0);
        }
         
    }
 
}