if (tokens [0].equalsIgnoreCase("getaverage")) {
	   int sum1=0;
	   int sum2=0;
	   int a=1;
	   for( i5=0 ; i5< student.size() ; i5++) {
		   if(student.get(i5).id.equalsIgnoreCase(tokens [1]) ) {
			for (int C=0 ; C< student.get(i5).courses.size(); C++ ) {
				sum1 += student.get(i5).courses.get(C).crh*student.get(i5).courses.get(C).grade;
				sum2 += student.get(i5).courses.get(C).crh;
			}
			System.out.printf("%f\n", (double) sum1/sum2);
			a=0;

		   }
	   }
	   if(a==1)
		   System.out.printf("This id is not exist\n");

   }