UVA - 10515 - Powers Et Al.

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.StringTokenizer;

public class Main {

    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        StringBuffer sb=new StringBuffer();
        int[]mods={1, 1, 4, 4, 2, 1, 1, 4, 4, 2};
        while(true){
            StringTokenizer st=new StringTokenizer(br.readLine());
            String str=st.nextToken();
            int m=Integer.parseInt(str.charAt(str.length()-1)+"");
            str=st.nextToken();
            int n;
            if(str.length()>1){
                n=Integer.parseInt(str.charAt(str.length()-2)+""+str.charAt(str.length()-1)+"");
            }else{
                n=Integer.parseInt(str.charAt(str.length()-1)+"");
            }
            if(m==0 && n==0 &&str.length()==1){
                break;
            }
            if(m==0 ||m==1 ||m==5 ||m==6){
                sb.append(m).append("\n");
            }else if(n==0){
                if(str.length()==1)
                    sb.append("1\n");
                else{
                    sb.append(modP(m, 4,mods)).append("\n");
                }
            }else{
                sb.append(modP(m, n,mods)).append("\n");
            }
        }
        System.out.print(sb);
    }
   
    static int modP(int m,int n,int[]mods){
        if(n%mods[m]>0)
            n= n%mods[m];
        else
            n=mods[m];
        int res=1;
        for (int i = 0; i < n; i++) {
            res*=m;
        }
        return res%10;
    }
}