В чем собственно проблема?
package com.javarush.task.task08.task0829;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;
/*
Модернизация ПО
*/
public class Solution {
public static void main(String[] args) throws IOException {
BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
List<String> cities = new ArrayList<>();
List<String> families = new ArrayList<>();
String city = reader.readLine();
cities.add(city);
while (true) {
String family = reader.readLine();
if (family.isEmpty()) {
break;
}
families.add(family);
}
String city1 = reader.readLine();
for(int i=0;i<cities.size();i++){
if(cities.get(i).equals(city1)){
System.out.println(families.get(i));
}
}
// Read the house number
/* int houseNumber = Integer.parseInt(reader.readLine());
if (0 <= houseNumber && houseNumber < list.size()) {
String familyName = list.get(houseNumber);
System.out.println(familyName);
}*/
}
}