Removes Duplicate Letters In a Word

public class NoRepetitionOfLettersInWord
{
    void input(String a)
    {
        String ch="";
        int i,j,l=a.length(),x=0;
        char p,q;
        String s=a.toLowerCase();
        for(i=0;i<l;i++)
        {
            p=s.charAt(i);
            for(j=i;j>=0;j--)
            {
                q=s.charAt(j);
                if(p==q)
                x++;
            }
            if(x==1)
            ch=ch+p;
            x=0;
        }
        System.out.println("Original Word="+s+"\nChanged Word="+ch);
    }
}