diff --git a/15/input.txt b/15/input.txt
new file mode 100644
index 0000000..20bb2f3
--- /dev/null
+++ b/15/input.txt
@@ -0,0 +1 @@
+11,0,1,10,5,19
\ No newline at end of file
diff --git a/15/part1.py b/15/part1.py
new file mode 100644
index 0000000..c868659
--- /dev/null
+++ b/15/part1.py
@@ -0,0 +1,21 @@
+
+
+
+def getStartingNumbers(filename):
+	with open(filename, "r") as f:
+		return [int(n) for n in f.read().split(",")]
+
+numbers = getStartingNumbers("input.txt")
+occurences = {n: [i] for i,n in enumerate(numbers)}
+
+while len(numbers) < 2020:
+	lastNumber = numbers[-1]
+	if len(occurences[lastNumber]) > 1:
+		number = occurences[lastNumber][-1] - occurences[lastNumber][-2]
+	else:
+		number = 0
+	occurences[number] = occurences.get(number, [])
+	occurences[number].append(len(numbers))
+	numbers.append(number)
+
+print(numbers[2019])
\ No newline at end of file
diff --git a/15/test.txt b/15/test.txt
new file mode 100644
index 0000000..37bfbbd
--- /dev/null
+++ b/15/test.txt
@@ -0,0 +1 @@
+3,2,1
\ No newline at end of file