public class MyClass {
public static int Sum(int n) {
return (n * (n + 1)) / 2;
}
public static void main(String args[]) {
int below10 = 9;
int sum = 3 * Sum((int)(below10 / 3)) + 5 * Sum((int)(below10 / 5)) - (3 * 5) * Sum((int)(below10 / 15));
System.out.print("sum = " + sum);
}
}
/*
run:
sum = 23
*/