def ReadMAtrix(RC):
    matrix = []
    print("Enter the entries rowwise:")

    for i in range(RC):
        a = []
        for j in range(RC):
            a.append(int(input()))
        matrix.append(a)
    return matrix

RC = int(input("Enter the number of rows and columns:"))
Mat=[]
Mat=ReadMAtrix(RC)
print('The main diameter in matrix : ')
for i in range(RC):
    print(Mat[i][i], end=" ")

print('\n The Bottom Triangular Matrix : ')
for i in range(RC):
    for j in range(RC):
        if i>=j:
           print(Mat[i][j], end=" ")
    print()