/* 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
	{
		System.out.println("a\\\\b\\\\c");
		System.out.println("a\\\\b\\\\c".replaceAll("\\\\\\\\", "\\\\"));
		//System.out.println("a\\\\b\\\\c".replaceAll("\\\\\\\\", "\\")); //runtime error
		System.out.println("a\\\\b\\\\c".replace("\\\\", "\\"));
	}
}

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

bm90aGluZw==

nothing