diff --git a/day15/input.txt b/day15/input.txt
new file mode 100644
index 0000000..6472b57
--- /dev/null
+++ b/day15/input.txt
@@ -0,0 +1,6 @@
+Disc #1 has 17 positions; at time=0, it is at position 15.
+Disc #2 has 3 positions; at time=0, it is at position 2.
+Disc #3 has 19 positions; at time=0, it is at position 4.
+Disc #4 has 13 positions; at time=0, it is at position 2.
+Disc #5 has 7 positions; at time=0, it is at position 2.
+Disc #6 has 5 positions; at time=0, it is at position 0.
diff --git a/day15/input_2.txt b/day15/input_2.txt
new file mode 100644
index 0000000..83e5290
--- /dev/null
+++ b/day15/input_2.txt
@@ -0,0 +1,7 @@
+Disc #1 has 17 positions; at time=0, it is at position 15.
+Disc #2 has 3 positions; at time=0, it is at position 2.
+Disc #3 has 19 positions; at time=0, it is at position 4.
+Disc #4 has 13 positions; at time=0, it is at position 2.
+Disc #5 has 7 positions; at time=0, it is at position 2.
+Disc #6 has 5 positions; at time=0, it is at position 0.
+Disc #7 has 11 positions; at time=0, it is at position 0.
diff --git a/day15/part1.js b/day15/part1.js
new file mode 100644
index 0000000..6e7c41e
--- /dev/null
+++ b/day15/part1.js
@@ -0,0 +1,22 @@
+var input = require("fs").readFileSync("input.txt").toString().replace(/\r/g, "");
+var cogs = input.split("\n").filter((a)=>(a)).map((line)=>{
+  var lineParts = line.match(/Disc #([1-9]+) has ([1-9]+) positions; at time=0, it is at position ([0-9]+)./);
+  return {
+    number: parseInt(lineParts[1]),
+    positions: parseInt(lineParts[2]),
+    startPos: parseInt(lineParts[3]),
+  };
+}).sort((a, b)=>(a.number - b.number));
+
+var t = -1;
+var solved = false;
+while(!solved){
+  solved = true;
+  t++;
+  for(var cog of cogs){
+    if(((cog.number + cog.startPos + t) % cog.positions) != 0){
+      solved = false;
+    }
+  }
+}
+console.log(t);
diff --git a/day15/part2.js b/day15/part2.js
new file mode 100644
index 0000000..0e60f36
--- /dev/null
+++ b/day15/part2.js
@@ -0,0 +1,22 @@
+var input = require("fs").readFileSync("input_2.txt").toString().replace(/\r/g, "");
+var cogs = input.split("\n").filter((a)=>(a)).map((line)=>{
+  var lineParts = line.match(/Disc #([1-9]+) has ([1-9]+) positions; at time=0, it is at position ([0-9]+)./);
+  return {
+    number: parseInt(lineParts[1]),
+    positions: parseInt(lineParts[2]),
+    startPos: parseInt(lineParts[3]),
+  };
+}).sort((a, b)=>(a.number - b.number));
+
+var t = -1;
+var solved = false;
+while(!solved){
+  solved = true;
+  t++;
+  for(var cog of cogs){
+    if(((cog.number + cog.startPos + t) % cog.positions) != 0){
+      solved = false;
+    }
+  }
+}
+console.log(t);