diff --git a/checksum.rb b/checksum.rb
new file mode 100644
index 0000000..61c72df
--- /dev/null
+++ b/checksum.rb
@@ -0,0 +1,32 @@
+a = "515	912	619	2043	96	93	2242	1385	2110	860	2255	621	1480	118	1230	99
+161	6142	142	1742	237	6969	211	4314	5410	4413	3216	6330	261	3929	5552	109
+1956	4470	3577	619	105	3996	128	1666	720	4052	108	132	2652	306	1892	1869
+2163	99	2257	895	112	1771	1366	1631	2064	2146	103	865	123	1907	2362	876
+1955	3260	1539	764	185	5493	5365	5483	4973	175	207	1538	4824	205	1784	2503
+181	3328	2274	3798	1289	2772	4037	851	1722	3792	175	603	725	158	2937	174
+405	247	2083	956	725	258	2044	206	2054	561	2223	2003	2500	355	306	2248
+837	937	225	1115	446	451	160	1219	56	61	62	922	58	1228	1217	1302
+1371	1062	2267	111	135	2113	1503	2130	1995	2191	129	2494	2220	739	138	1907
+3892	148	2944	371	135	1525	3201	3506	3930	3207	115	3700	2791	597	3314	132
+259	162	186	281	210	180	184	93	135	208	88	178	96	25	103	161
+1080	247	1036	936	108	971	908	1035	123	974	103	1064	129	1189	1089	938
+148	1874	122	702	922	2271	123	111	454	1872	2142	2378	126	813	1865	1506
+842	267	230	1665	2274	236	262	1714	3281	4804	4404	3833	661	4248	3893	1105
+1112	1260	809	72	1104	156	104	1253	793	462	608	84	99	1174	449	929
+707	668	1778	1687	2073	1892	62	1139	908	78	1885	800	945	712	57	65"
+
+splitted = a.split("\n").map! {|i| i.split("\t").map(&:to_i)}
+puts splitted.reduce(0) {|sum, row| sum += row.max-row.min}
+
+result = 0
+splitted.each do |row|
+  row.permutation(2).to_a.find do |ele|
+    if (ele[0].lcm(ele[1]) == ele[0]) then
+      result += ele[0] / ele[1]
+    end
+  end
+end
+
+puts result
+
+