public class JavaApplication6{
    public static int diagonalCount(int [][]arr){
        int len = arr.length;
        int total = 0;
        for(int i = 0; i < len; i++){
            total += arr[i][i];
        }
        return total;
    }

    public static int lowerCount(int [][]arr){
        int len = arr.length;
        int total = 0;
        for(int i = 0; i < len; i++){
            for(int j =0; j < len; j++){
                if(j < i){
                    total += arr[i][j];
                }
            }
        }
        return total;
    }

    public static void main(String[] args) {
        int [][]arr  = {{1,2,3},{4,5,6},{7,8,9}};
        System.out.println(diagonalCount(arr));
        System.out.println(lowerCount(arr));
    }
}