/* package whatever; // don't place package name! */
 
import java.util.*;
import java.lang.*;
import java.io.*;
 
/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{
	public static void main (String[] args) throws java.lang.Exception
	{
		// your code goes here
		HashMap<String,String> map = new HashMap<String,String>();
		map.put("key1", "1");
		map.put("key2", "2");
		map.put("key3", "1");
		map.put("key4", "4");
		final Set<String> keys = map.keySet();
		for (final Iterator<String> it = keys.iterator(); it.hasNext(); ) {
			final String key = it.next();
			if (map.get(key) != null && map.get(key).equals("1")) {
				System.out.println(key);
				it.remove();
			}
		}
		System.out.println(map.size());
	}
}

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