there was a code given in my text book about finding the avg between 3 no. works in blueJ but not in intelliJ. how do i use this code in intelliJ?

Question

Why doesn't this work in IntelliJ?

public class main {
    public static void main(int A, int B, int C){
        int sum = 0;
        double avg = 0.0;
        sum = (A+B+C);
        avg = (double)sum/3.0;
        System.out.println("the sum ="+ sum);
        System.out.println("the average = "+ avg);

    }
}