diff --git a/15/o.py b/15/o.py
new file mode 100644
index 0000000..4b63982
--- /dev/null
+++ b/15/o.py
@@ -0,0 +1,67 @@
+import os
+
+input = open(os.path.dirname(__file__) +
+             "/input-demo.txt", "r").readlines()
+
+beacons = []
+sensors = []
+distance = []
+
+for line in input:
+    l = line.strip().split()
+    sx = int(l[2].split('=')[1].split(',')[0])
+    sy = int(l[3].split('=')[1].split(':')[0])
+    bx = int(l[8].split('=')[1].split(',')[0])
+    by = int(l[9].split('=')[1])
+    d = abs(bx-sx)+abs(by-sy)
+    distance.append(d)
+    beacons.append((bx, by))
+    sensors.append((sx, sy))
+    print(sx, sy, bx, by, d)
+
+
+def getcoverage(b, Y):
+    coverage = set()
+    (x, y) = sensors[b]
+    d0 = distance[i]
+    print("check", x, y, d0)
+    for X in range(x-d0, x+d0):
+        if (abs(x-X)+abs(y-Y)) <= d0:
+            coverage.add((X, Y))
+
+        # for Y in range(y-d0, y+d0):
+            #print(X, Y, abs(x-X)+abs(y-Y))
+
+    return coverage
+
+
+#testy = 2000000
+testy = 10
+
+fullcoverage = set()
+for i in range(len(sensors)):
+    cov = getcoverage(i, testy)
+    # print(cov)
+    fullcoverage.update(cov)
+
+# print(fullcoverage)
+
+
+testset = set()
+for s in fullcoverage:
+    if s[1] == testy:
+        testset.add(s)
+
+nonbeacons = testset.difference(set(beacons))
+
+# print(sorted(set(beacons)))
+# print(sorted(testset))
+
+
+for b in beacons:
+    if b[1] == testy:
+        print(b[0]*4000000+b[1])
+
+
+print(len(testset))
+print(len(nonbeacons))