import java.util.*;

class Solution {
    public int solution(String S, int K) {
		if(K < 1)
            return -1;

        String[] words = S.split("\\s");

        int numberOfSms = 0;
        int smsLength = 0;
        for(int i = 0; i < words.length; i++){

            int nextWordLength = words[i].length() ;

            if(nextWordLength > K)
                return -1;

            if(smsLength != 0){
                if(smsLength + nextWordLength <= K){
                    smsLength += nextWordLength +1;
                }else{
                    numberOfSms++;
                    smsLength = nextWordLength +1;
                }
            }else{
                numberOfSms++;
                smsLength = nextWordLength +1;
            }
        }
        return numberOfSms;
    }
}


// one class needs to have a main() method
public class HelloWorld
{
  // arguments are passed using the text field below this editor
  public static void main(String[] args)
  {
    Solution myObject = new Solution();
    System.out.print(myObject.solution("SMS messages are really gooood", 12));
    System.out.print(myObject.solution("oen one one", 3));
    System.out.print(myObject.solution("oen one one one one", 3));
  }
}