WHERE TO PUT THE CODE

I HAVE A PROGRAM HERE THAT COMPUTES FOR I/O UTILIZATION. THERE'S ONLY ONE PROBLEM, I CANT SEEM TO FIND THE RIGHT PLACE TO PUT THESE CODE:

CPU=(mss/(ms+mss+msss))*100;
JOptionPane.showMessageDialog(null, "CPU Utlization:"+CPU+"%");

AS YOU CAN SEE I PLACED THE CODE ON THE LAST PART BUT WHEN I COMPILE THERE'S AN ERROR SAYING
"variable ms might not have been initialized"

BUT I ALREADY DID INITIALIZE VARIABLE ms.

PLEASE LET ME KNOW WHERE TO PUT THE CODE SO THAT THE PROGRAM CAN FUNCTION RIGHT. THANKS

import javax. swing.*;

public class CaseStudy{
public static void main(String[]args){
double ms, mss, msss, mssss, CPU; int input,charc,unit,unit1,unit2,unit3,unit4,card,output,lines,inst;
double sec=.010;

{

//INPUT PHASE
input=Integer.parseInt(JOptionPane.showInputDialog("Choose Input Device: \n (1)Keyboard \n (2)Cardreader"));
{

if (input==1){
charc=Integer.parseInt(JOptionPane.showInputDialog("How Many Characters?"));
unit=Integer.parseInt(JOptionPane.showInputDialog("Number Of Characters:"+charc+"\n In What Unit Of Time?\n(1)Microsecond \n(2)Millisecond\n(3)Second \n(4)Minute"));
if (unit==1)
mssss=(sec/charc);
else if (unit==2)
mssss=(1/charc);
else if (unit==3)
mssss=(1000/charc);
else
mssss=(60000/charc);

JOptionPane.showMessageDialog(null, "Input Phase:"+mssss+"ms");}

else{
card=Integer.parseInt(JOptionPane.showInputDialog("How Many Cards?"));
unit2=Integer.parseInt(JOptionPane.showInputDialog("Number Of Characters:"+card+"\n In What Unit Of Time?\n(1)Microsecond \n(2)Millisecond\n(3)Second \n(4)Minute"));
if (unit2==1)
ms=(sec/card);
else if (unit2==2)
ms=(1/card);
else if (unit2==3)
ms=(1000/card);
else
ms=(60000/card);
JOptionPane.showMessageDialog(null, "Input Phase:"+ms+"ms");}}

//OUTPUT PHASE
output=Integer.parseInt(JOptionPane.showInputDialog("Choose Printer: (1)Laser (2)DotMatrix"));
{if (input==1){
lines=Integer.parseInt(JOptionPane.showInputDialog("How Many Lines?"));
unit3=Integer.parseInt(JOptionPane.showInputDialog("Number Of Lines:"+lines+"\n In What Unit Of Time?\n(1)Microsecond \n(2)Millisecond\n(3)Second \n(4)Minute"));
if (unit3==1)
msss=(sec/lines);
else if (unit3==2)
msss=(1/lines);
else if (unit3==3)
msss=(1000/lines);
else
msss=(60000/lines);
JOptionPane.showMessageDialog(null, "Output Phase:"+msss+"ms");}
else{
lines=Integer.parseInt(JOptionPane.showInputDialog("How Many Lines?"));
unit3=Integer.parseInt(JOptionPane.showInputDialog("Number Of Lines:"+lines+"\n In What Unit Of Time?\n(1)Microsecond \n(2)Millisecond\n(3)Second \n(4)Minute"));
if (unit3==1)
msss=(sec/lines);
else if (unit3==2)
msss=(1/lines);
else if (unit3==3)
msss=(1000/lines);
else
msss=(60000/lines);
JOptionPane.showMessageDialog(null, "Output Phase:"+msss+"ms");}}

//PROCESS PHASE
inst=Integer.parseInt(JOptionPane.showInputDialog("How Many Instructions?"));
unit4=Integer.parseInt(JOptionPane.showInputDialog("Instructions:"+inst+"\n In What Unit Of Time?\n(1)Microsecond \n(2)Millisecond\n(3)Second \n(4)Minute"));
{if (unit4==1)
mss=(inst/1000);
else if (unit4==2)
mss=(inst/1);
else if (unit4==3)
mss=(inst/sec);
else
mss=(inst/60000);
JOptionPane.showMessageDialog(null, "Process Phase:"+mss+"ms");
//CPU Utilization
CPU=(mss/(ms+mss+msss))*100;
JOptionPane.showMessageDialog(null, "CPU Utlization:"+CPU+"%");}

}}}

The compiler is telling you that there are certain code paths where the variable "ms" may not have been set to something. If you don't think that that can happen then simply initialize ms to zero.