diff --git a/src/problem/mod.rs b/src/problem/mod.rs
index 9e45355..a015793 100644
--- a/src/problem/mod.rs
+++ b/src/problem/mod.rs
@@ -1,19 +1,19 @@
-mod p0001_two_sum;
-mod p0009_palindrome_number;
-mod p0020_valid_parentheses;
+mod p1_two_sum;
+mod p9_palindrome_number;
+mod p20_valid_parentheses;
 mod p2697_lexicographically_smallest_palindrome;
-mod p0002_add_two_numbers;
-mod p0003_longest_substring_without_repeating_characters;
-mod p0162_find_peak_element;
+mod p2_add_two_numbers;
+mod p3_longest_substring_without_repeating_characters;
+mod p162_find_peak_element;
 mod p2828_check_if_a_string_is_an_acronym_of_words;
 mod p0052_n_queens_ii;
-mod p0912_sort_an_array;
+mod p912_sort_an_array;
 mod p1276_number_of_burgers_with_no_waste_of_ingredients;
-mod p0006_zigzag_conversion;
-mod p0007_reverse_integer;
-mod p0004_median_of_two_sorted_arrays;
-mod p0743_network_delay_time;
-mod p0447_number_of_boomerangs;
+mod p6_zigzag_conversion;
+mod p7_reverse_integer;
+mod p4_median_of_two_sorted_arrays;
+mod p743_network_delay_time;
+mod p447_number_of_boomerangs;
 mod p2085_count_common_words_with_one_occurrence;
 mod p2182_construct_string_with_repeat_limit;
 mod p83_remove_duplicates_from_sorted_list;
diff --git a/src/problem/p0162_find_peak_element.rs b/src/problem/p162_find_peak_element.rs
similarity index 100%
rename from src/problem/p0162_find_peak_element.rs
rename to src/problem/p162_find_peak_element.rs
diff --git a/src/problem/p0001_two_sum.rs b/src/problem/p1_two_sum.rs
similarity index 100%
rename from src/problem/p0001_two_sum.rs
rename to src/problem/p1_two_sum.rs
diff --git a/src/problem/p0020_valid_parentheses.rs b/src/problem/p20_valid_parentheses.rs
similarity index 100%
rename from src/problem/p0020_valid_parentheses.rs
rename to src/problem/p20_valid_parentheses.rs
diff --git a/src/problem/p0002_add_two_numbers.rs b/src/problem/p2_add_two_numbers.rs
similarity index 100%
rename from src/problem/p0002_add_two_numbers.rs
rename to src/problem/p2_add_two_numbers.rs
diff --git a/src/problem/p0003_longest_substring_without_repeating_characters.rs b/src/problem/p3_longest_substring_without_repeating_characters.rs
similarity index 100%
rename from src/problem/p0003_longest_substring_without_repeating_characters.rs
rename to src/problem/p3_longest_substring_without_repeating_characters.rs
diff --git a/src/problem/p0447_number_of_boomerangs.rs b/src/problem/p447_number_of_boomerangs.rs
similarity index 100%
rename from src/problem/p0447_number_of_boomerangs.rs
rename to src/problem/p447_number_of_boomerangs.rs
diff --git a/src/problem/p0004_median_of_two_sorted_arrays.rs b/src/problem/p4_median_of_two_sorted_arrays.rs
similarity index 100%
rename from src/problem/p0004_median_of_two_sorted_arrays.rs
rename to src/problem/p4_median_of_two_sorted_arrays.rs
diff --git a/src/problem/p0006_zigzag_conversion.rs b/src/problem/p6_zigzag_conversion.rs
similarity index 100%
rename from src/problem/p0006_zigzag_conversion.rs
rename to src/problem/p6_zigzag_conversion.rs
diff --git a/src/problem/p0743_network_delay_time.rs b/src/problem/p743_network_delay_time.rs
similarity index 100%
rename from src/problem/p0743_network_delay_time.rs
rename to src/problem/p743_network_delay_time.rs
diff --git a/src/problem/p0007_reverse_integer.rs b/src/problem/p7_reverse_integer.rs
similarity index 100%
rename from src/problem/p0007_reverse_integer.rs
rename to src/problem/p7_reverse_integer.rs
diff --git a/src/problem/p0912_sort_an_array.rs b/src/problem/p912_sort_an_array.rs
similarity index 100%
rename from src/problem/p0912_sort_an_array.rs
rename to src/problem/p912_sort_an_array.rs
diff --git a/src/problem/p0009_palindrome_number.rs b/src/problem/p9_palindrome_number.rs
similarity index 100%
rename from src/problem/p0009_palindrome_number.rs
rename to src/problem/p9_palindrome_number.rs