Maybe its' a typo... I don't know
package com.codegym.task.task08.task0828;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import java.util.*;
import java.io.*;
/*
Month number
*/
public class Solution {
public static void main(String[] args) throws IOException {
Scanner scan = new Scanner(System.in);
String s = scan.nextLine();
ArrayList<String> list = new ArrayList<>();
list.add("January");
list.add("February");
list.add("March");
list.add("April");
list.add("May");
list.add("Jun");
list.add("July");
list.add("August");
list.add("September");
list.add("October");
list.add("November");
list.add("December");
for (int i = 0; i<list.size(); i++){
if (s.equals(list.get(i))) {
System.out.println(s +" is month "+ (i+1));
}
}
}
}