diff --git a/4/onestar-1.py b/4/onestar-1.py
new file mode 100644
index 0000000..a767e27
--- /dev/null
+++ b/4/onestar-1.py
@@ -0,0 +1,25 @@
+elves = []
+count = 0
+with open("input.txt", "r") as f:
+    for line in f.readlines():
+        line = line.strip("\n")
+        # "A-B,C-D"
+        twoelves = line.split(",")
+        # ["A-B", "C-D"]
+
+        # "A-B"
+        leftelf = twoelves[0].split("-")
+        # ["A", "B"]
+        lb1 = int(leftelf[0])
+        ub1 = int(leftelf[1])
+
+        # "C-D"
+        rightelf = twoelves[1].split("-")
+        # ["C", "D"]
+        lb2 = int(rightelf[0])
+        ub2 = int(rightelf[1])
+
+        if ((lb1 <= lb2 and ub1 >= ub2) or # Elf 1 fully covers elf 2
+            (lb2 <= lb1 and ub2 >= ub1)): # Elf 2 fully covers elf 1
+            count += 1
+print(count)
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