UVA - 11661 - Burger Time

import java.io.*;
import java.util.IllegalFormatException;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import javax.swing.JFileChooser;
import javax.swing.JOptionPane;

public class Main{

    public static void main(String[] args) throws FileNotFoundException {
        TextIO.readStream(System.in);

        while(true){
            int x=TextIO.getlnInt();
            if(x==0)
                break;
            String temp=TextIO.getlnString();
            int mindist=Integer.MAX_VALUE;
            int lastindex=0;
            char lastchar=' ';
            for(int i=0;i<x;i++){
                if(temp.charAt(i)=='Z'){
                    mindist=0;
                    break;
                     }
                if(lastchar==' ' ||temp.charAt(i)=='.'){
                    if(temp.charAt(i)=='.'){}
                    else{
                       lastchar=temp.charAt(i);
                       lastindex=i;
                    }
                }else{
                   if(temp.charAt(i)==lastchar)
                       lastindex=i;
                   if(temp.charAt(i)!=lastchar){
                       int value=i-lastindex;
                       if(value<mindist)
                           mindist=value;
                       lastchar=temp.charAt(i);
                       lastindex=i;
                   }
                }
 
            }
            System.out.println(mindist);
        }
}
}