import numpy as np

def diag_zero(matrix):
    # Set values above the diagonal to zero
    for i in range(matrix.shape[0]):
        for j in range(i+1, matrix.shape[1]):
            matrix[i, j] = 0
    
    # Output the resulting matrix
    print("Resulting matrix:")
    print(matrix)
    
    # Calculate the sum of the remaining values
    remaining_sum = np.sum(matrix)
    
    # Output the sum
    print("Sum of remaining values:", remaining_sum)
    
    return remaining_sum