diff --git a/2020/day1/day1.ex b/2020/day1/day1.ex
new file mode 100644
index 0000000..cff47c1
--- /dev/null
+++ b/2020/day1/day1.ex
@@ -0,0 +1,21 @@
+defmodule Day1 do
+  def all_pairs(list) do
+    Enum.reduce(0..(length(list) - 1), [], fn idx, pairs ->
+      item = Enum.at(list, idx)
+      other_items = Enum.slice(list, (idx + 1)..(length(list) - 1))
+      new_pairs = Enum.map(other_items, fn elt -> {item, elt} end)
+      pairs ++ new_pairs
+    end)
+  end
+
+  def part1(input) do
+    lines = String.split(input)
+    ints = Enum.map(lines, fn line -> String.to_integer(line) end)
+    pairs = Day1.all_pairs(ints)
+    [{a, b}] = Enum.filter(pairs, fn {a, b} -> a + b == 2020 end)
+    a * b
+  end
+end
+
+input = File.read!("input.txt")
+IO.inspect(Day1.part1(input))
diff --git a/2020/day1/input.txt b/2020/day1/input.txt
new file mode 100644
index 0000000..3c039b7
--- /dev/null
+++ b/2020/day1/input.txt
@@ -0,0 +1,200 @@
+1895
+1732
+1660
+1658
+1878
+367
+2010
+1989
+431
+1946
+1614
+2003
+945
+1856
+1934
+1937
+1781
+1947
+1991
+1917
+1604
+1707
+1966
+1959
+1182
+1828
+1880
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+1942
+1687
+1611
+1922
+1913
+1803
+1976
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+1971
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+1912
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+1901
+1941
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+1975
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+1833
+1951
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+1926
+1931
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+657
+1872
+1933
+1961
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+1998
+1994
+418
+1914
+1929
+1810
+2009
+1712
+830
+1990
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+1753
+1859
+1965
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+1905
+1921
+1685
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+1899
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+1927
+1952
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+1960
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+1616
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+2005
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+1915
+1663
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+1902
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+1875
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+1873
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+1808
+1884
+1916
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+1835
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+1774
+1764
+1609
+1882
+1857
+2004
+1911
+1896
+1980
+2006
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+2008
+1972
+1648
+1923
+1978
+1675
+1831
diff --git a/README.md b/README.md
index fb0377d..fa32a13 100644
--- a/README.md
+++ b/README.md
@@ -5,9 +5,9 @@ I like solving the [Advent of Code](https://adventofcode.com/) challenges every
 - 2017: Python but like a Go programmer
 - 2018: Rust
 - 2019: Ruby
-- 2020: TODO
+- 2020: Elixir
 
 Languages I'd like to use for the TODO years:
-- Elixir
 - WebAssembly
 - Haskell
+- J (or other APL-like)