import java.util.*;
import java.lang.*;
import java.io.*;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
 
class Ideone
{
	public static void main (String[] args) throws java.lang.Exception
	{
		String[] strings = { 
			"71346 G249 USD 70045620 27/08/2020 001 / 004",
            "71346 G249 USD 70045620/2020 27/08/2020 001 / 004"
		};
		String regex = "\\b[0-9]{6,}(?:/[0-9]{4})?";
 
		Pattern pattern = Pattern.compile(regex);
 
 
		for (String s : strings) {
			Matcher matcher = pattern.matcher(s);
			if (matcher.find()) {
    			System.out.println(matcher.group(0));
			}
		}
	}
}

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