diff --git a/src/main/java/practice/CandidateValidator.java b/src/main/java/practice/CandidateValidator.java
index d6d40c65b..ad64f0716 100644
--- a/src/main/java/practice/CandidateValidator.java
+++ b/src/main/java/practice/CandidateValidator.java
@@ -1,18 +1,25 @@
 package practice;
 
-import model.Candidate;
-
 import java.util.function.Predicate;
+import model.Candidate;
 
 public class CandidateValidator implements Predicate<Candidate> {
-
     @Override
     public boolean test(Candidate candidate) {
-        String[] PeriodsInUkr = candidate.getPeriodsInUkr().split("-");
+        periodsInUkrValidator(candidate);
+        String[] periodsInUkr = candidate.getPeriodsInUkr().split("-");
         return candidate.getAge() >= 35
                 && candidate.getNationality().equals("Ukrainian")
                 && candidate.isAllowedToVote()
-                && Integer.parseInt(PeriodsInUkr[1]) - Integer.parseInt(PeriodsInUkr[0]) > 10;
+                && Integer.parseInt(periodsInUkr[1]) - Integer.parseInt(periodsInUkr[0]) > 10;
+    }
+
+    private void periodsInUkrValidator(Candidate candidate) {
+        for (int i = 0; i < candidate.getPeriodsInUkr().length(); i++) {
+            if (Character.isLetter(candidate.getPeriodsInUkr().charAt(i))) {
+                throw new RuntimeException("Data contains letters");
+            }
+        }
     }
     //write your code here
 }
diff --git a/src/main/java/practice/StreamPractice.java b/src/main/java/practice/StreamPractice.java
index 9c73c9ca8..807eaf490 100644
--- a/src/main/java/practice/StreamPractice.java
+++ b/src/main/java/practice/StreamPractice.java
@@ -1,9 +1,10 @@
 package practice;
 
-import java.util.*;
-import java.util.function.Predicate;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.List;
+import java.util.NoSuchElementException;
 import java.util.stream.IntStream;
-
 import model.Candidate;
 import model.Cat;
 import model.Person;
@@ -17,11 +18,13 @@ public class StreamPractice {
      * "Can't get min value from list: < Here is our input 'numbers' >"
      */
     public int findMinEvenNumber(List<String> numbers) {
+        dataValidatorForFindMinEvenNumber(numbers);
         return numbers.stream().map(s -> s.split(","))
                 .flatMap(Arrays::stream)
                 .mapToInt(Integer::valueOf)
                 .filter(i -> i % 2 == 0)
-                .min().orElseThrow(() -> new RuntimeException("Can't get min value from list: " + numbers));
+                .min().orElseThrow(() -> new RuntimeException("Can't get min value from list: "
+                        + numbers));
     }
 
     /**
@@ -47,7 +50,9 @@ public Double getOddNumsAverage(List<Integer> numbers) {
      */
     public List<Person> selectMenByAge(List<Person> peopleList, int fromAge, int toAge) {
         return peopleList.stream()
-                .filter(i -> i.getAge() >= fromAge && i.getAge() <= toAge && i.getSex().equals(Person.Sex.MAN))
+                .filter(i -> i.getAge() >= fromAge
+                        && i.getAge() <= toAge
+                        && i.getSex().equals(Person.Sex.MAN))
                 .toList();
     }
 
@@ -77,7 +82,7 @@ public List<Person> getWorkablePeople(int fromAge, int femaleToAge,
      */
     public List<String> getCatsNames(List<Person> peopleList, int femaleAge) {
         return peopleList.stream()
-                .filter(i -> i.getAge() > femaleAge && i.getSex().equals(Person.Sex.WOMAN))
+                .filter(i -> i.getAge() >= femaleAge && i.getSex().equals(Person.Sex.WOMAN))
                 .map(Person::getCats)
                 .flatMap(Collection::stream)
                 .map(Cat::getName)
@@ -104,4 +109,15 @@ public List<String> validateCandidates(List<Candidate> candidates) {
                 .sorted()
                 .toList();
     }
+
+    private void dataValidatorForFindMinEvenNumber(List<String> data) {
+        for (String datas : data) {
+            for (int i = 0; i < datas.length(); i++) {
+                if (Character.isLetter(datas.charAt(i))) {
+                    throw new RuntimeException("Data contains letters");
+
+                }
+            }
+        }
+    }
 }