/**
knakul853
**/

class Solution {
            string les_than_20 [20]={"","One","Two","Three","Four","Five","Six","Seven","Eight","Nine","Ten","Eleven","Twelve","Thirteen","Fourteen","Fifteen","Sixteen","Seventeen","Eighteen","Nineteen"};
        string tens [20]= {"", "Ten", "Twenty", "Thirty", "Forty", "Fifty", "Sixty", "Seventy", "Eighty", "Ninety"};

        string thousands[5]={"", "Thousand", "Million", "Billion"};
public:
    string numberToWords(int num) {
        if(num==0)return "Zero";
        string ans="";
        //x1x2x3x4x5x6x7
        int i=0;

            while(num)
            {
                if(num%1000!=0){

                  string temp="";
                f(temp, num % 1000);
                ans = temp + thousands[i] +" "+ ans;
                }

                num/=1000;
                i++;
            }
            i=(int)ans.size()-1;
        while(i >=0 && ans[i]==' ')ans.pop_back(), i--;

        return ans;
     }

      public:
 void f(string &temp, int n)
   {
     cout<<n<<"\n";
      if(n==0)return;
       if(n<20){
           temp += les_than_20[ n ] + " ";
           return;
       }
       if(n<100){
           temp += tens[n/10]+" ";
           f(temp, n %10);
           return;
       }

          temp += les_than_20[n/100]+" Hundred ";
        f(temp, n%100);
         return;

   }


};