/in/Main.java:2: error: class A is public, should be declared in a file named A.java
public class A{
       ^
/in/Main.java:5: error: variable a is already defined in method main(int)
		int a=scanner.nextInt();
		    ^
/in/Main.java:5: error: cannot find symbol
		int a=scanner.nextInt();
		      ^
  symbol:   variable scanner
  location: class A
/in/Main.java:6: error: cannot find symbol
		int b=scanner.nextInt();
		      ^
  symbol:   variable scanner
  location: class A
4 errors