diff --git a/src/lib.rs b/src/lib.rs
index e595a86..7c0c3eb 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -65,6 +65,12 @@ pub mod day2 {
         let invalid_sum: u64 = invalid.sum();
         invalid_sum.to_string()
     }
+    pub fn day2_part2(input: &str) -> String {
+        let ranges = parse(input);
+        let invalid = ranges.into_iter().flatten().filter(|&id| !is_id_doubly_valid(id));
+        let invalid_sum: u64 = invalid.sum();
+        invalid_sum.to_string()
+    }
     fn parse(input: &str) -> Vec<RangeInclusive<u64>> {
         input
             .split(',')
@@ -82,12 +88,27 @@ pub mod day2 {
             first_half != second_half
         }
     }
+    fn is_id_doubly_valid(id: u64) -> bool {
+        let chars = id.to_string().chars().collect::<Vec<char>>();
+        let charnum = chars.len();
+        for chunk_count in 2..=charnum {
+            if charnum % chunk_count != 0 {
+                continue;
+            }
+            let chunks = chars.chunks_exact(charnum / chunk_count).collect::<Vec<_>>();
+            if chunks.iter().all(|&chunk| chunk == chunks[0]) {
+                return false
+            }
+        }
+        true
+    }
 }
 
 #[cfg(test)]
 mod tests {
     use super::*;
 
+    #[ignore]
     #[test]
     fn day2_part1_test() {
         let test_result = day2::day2_part1(include_str!("../input/day2.test.txt"));
@@ -95,6 +116,14 @@ mod tests {
         let result = day2::day2_part1(include_str!("../input/day2.txt"));
         assert_eq!(result, "38158151648");
     }
+    #[ignore]
+    #[test]
+    fn day2_part2_test() {
+        let test_result = day2::day2_part2(include_str!("../input/day2.test.txt"));
+        assert_eq!(test_result, "4174379265");
+        let result = day2::day2_part2(include_str!("../input/day2.txt"));
+        assert_eq!(result, "45283684555");
+    }
 
     #[test]
     fn day1_part1_test() {