import java.util.*;
import java.lang.*;
import java.io.*;
import java.util.regex.*;
 
class Ideone
{
	{
		String str 
= "hello   hello world world world world"; 		String pat 
= "\\b(\\w+)(?:\\s+\\1\\b)+"; 		String res 
= str.
replaceAll(pat, 
"$1"); 	}
}
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