Using Hashmap making plagiarism checker based on Java - hashmap

Question

it reads input.txt file and compared with target file.
If more than 3words are same as input file, the program should say plagiarized from .
I used substring so the program only compares first 3 letters.
should use tokenized? or how can it compared
Here is my code
import java.io.File;
import java.io.FileNotFoundException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Scanner;
public class CheckPlagiarism{
public static void main(String args[]) throws FileNotFoundException
{
//Init HashMap
HashMap<String, Integer> corpus = new HashMap<>();
String fileName = args[0];
String tragetName = args[1];
int matchCount = Integer.parseInt(args[2]);
Scanner scanner = new Scanner(new File(fileName));
while(scanner.hasNext())
{
String[] line = scanner.nextLine().split(":");
corpus.put(line[1], Integer.parseInt(line[0]));
}
boolean found = false;
scanner = new Scanner(new File(tragetName));
while(scanner.hasNext())
{
String line = scanner.nextLine();
line = line.string(0,matchCount);
for(Entry<String, Integer> temp: corpus.entrySet()){
String key=temp.getKey();
if(key.contains(line))
{
System.out.println("Plagiarized from " + temp.getValue());
found = true;
break;
}
}
}
if(!found)
{
System.out.println("Not Plagiarized");
}
}
}