Can someone suggest what's wrong in logic

/* package codechef; // don’t place package name! */

import java.util.;
import java.lang.
;
import java.io.*;
import java.lang.Math;

/* Name of the class has to be “Main” only if the class is public. */
class Codechef
{
public static void main (String[] args) throws java.lang.Exception
{
// your code goes herene
int sum=0;
Scanner sc=new Scanner(System.in);
int t=sc.nextInt();
int a[]=new int[26];
while(t–>0){
sum=0;
String s=sc.next();
s=s.toLowerCase();
int n=s.length();
for(int m=0;m<26;m++)
a[m] = 0;
for(int i=0;i<n;i++)
{
a[s.charAt(i)-‘a’]++;
}

	    for(int j=0;j<26;j++)
	    {
	        if(a[j]==0)
	        continue;
	        sum=(int)(sum+Math.ceil((a[j])/2.0));
	    }
	    System.out.println(sum);
	}
}

}

//