Compile error in CVOTE problem

the following code is compiling and running fine in my system for the problem CVOTE. however, it fails to compile in codeshef. Can someone please explain why??

import java.util.*;

public class Main {

public static void main (String[] args){
    Scanner scn = new Scanner(System.in);
    int n=scn.nextInt();
    int m=scn.nextInt();

    HashMap hm1 = new HashMap();        //chef and votes
    HashMap hm2 = new HashMap();        // country and votes
    HashMap hm3 = new HashMap();        // input- chef and country

    for(int i=0;i<n;i++){
        String key = scn.next();
        String value=scn.next();
        String temp=scn.nextLine();
        hm3.put(key, value);
    }
    Set set = hm3.keySet();
    Iterator hmitr = set.iterator();

    while(hmitr.hasNext()){
        Object key1= hmitr.next();
        Object value1= hm3.get(key1);
        hm1.put(key1,0);
        hm2.put(value1,0);
    }

   for(int i=0;i<m;i++){
       String candidate= scn.nextLine();
       hm1.put(candidate,(int)hm1.get(candidate)+1);
       hm2.put(hm3.get(candidate),(int) hm2.get(hm3.get(candidate))+1);
   }

   String bestcountry="zzzzzzzzzz";
   int maxvotes=0;
   set=hm2.keySet();
   hmitr=set.iterator();
   while(hmitr.hasNext()){
       String country= (String)hmitr.next();
       if((int)hm2.get(country)>maxvotes){
           maxvotes=(int)hm2.get(country);
           bestcountry=country;
       }
       if((int)hm2.get(country)==maxvotes){
           bestcountry= (bestcountry.compareTo(country))<0 ?bestcountry:country;
       }
   }
   System.out.println(bestcountry);




   String bestcandidate="zzzzzzzzzz";
   maxvotes=0;
   set=hm1.keySet();
   hmitr=set.iterator();
   while(hmitr.hasNext()){
       String candidate= (String)hmitr.next();
       if((int)hm1.get(candidate)>maxvotes){
           maxvotes=(int)hm1.get(candidate);
           bestcandidate=candidate;
       }
       if((int)hm1.get(candidate)==maxvotes){
           bestcandidate= (bestcandidate.compareTo(candidate))<0 ?bestcandidate:candidate;
       }
   }
   System.out.println(bestcandidate);

}

}

Error shown by codeshef-

Main.java:32: inconvertible types found : java.lang.Object required: int hm1.put(candidate,(int)hm1.get(candidate)+1); ^ Main.java:32: operator + cannot be applied to ,int hm1.put(candidate,(int)hm1.get(candidate)+1); ^ Main.java:33: inconvertible types found : java.lang.Object required: int hm2.put(hm3.get(candidate),(int) hm2.get(hm3.get(candidate))+1); ^ Main.java:33: operator + cannot be applied to ,int hm2.put(hm3.get(candidate),(int) hm2.get(hm3.get(candidate))+1); ^ Main.java:42: inconvertible types found : java.lang.Object required: int if((int)hm2.get(country)>maxvotes){ ^ Main.java:43: inconvertible types found : java.lang.Object required: int maxvotes=(int)hm2.get(country); ^ Main.java:46: inconvertible types found : java.lang.Object required: int if((int)hm2.get(country)==maxvotes){ ^ Main.java:61: inconvertible types found : java.lang.Object required: int if((int)hm1.get(candidate)>maxvotes){ ^ Main.java:62: inconvertible types found : java.lang.Object required: int maxvotes=(int)hm1.get(candidate); ^ Main.java:65: inconvertible types found : java.lang.Object required: int if((int)hm1.get(candidate)==maxvotes){ ^ Note: Main.java uses unchecked or unsafe operations. Note: Recompile with -Xlint:unchecked for details. 10 errors

Thanx in advance!!!