How to add number in nasm assembly [duplicate]

Question

I have the following variables (x,y) that I read user provided data into and then attempt to add them and finally outputting the result to the terminal

section .bss

        ; first number
        x resb 5

        ; second number
        y resb 5

        ; sum 
        z resb 10

this is out I am trying to add them

    ; sum the two numbers
    mov eax, x      ; moves the value of x into eax register
    add eax, y      ; adds value of y to what ever value is in eax 
  


    ; Output value of z
    mov eax, 4  ; system call (sys_write)
    mov ebx, 1  ; file descriptor (stdout)
    mov ecx, z  ; 
    mov edx, 10 ;
    int 0x80    ; kernel call

this is the output of my program

welcome please enter two numbers 
Enter first number 
123
Enter second number 
23
                    

why am i getting an empty line for the value of z