From 3cc48c7648821dc47995874e3e0c7eca7dd1b223 Mon Sep 17 00:00:00 2001
From: "Felix C. Stegerman" <flx@obfusk.net>
Date: Sat, 24 Sep 2016 13:28:47 +0200
Subject: [PATCH] ...

---
 f.py | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)
 create mode 100644 f.py

diff --git a/f.py b/f.py
new file mode 100644
index 0000000..a131572
--- /dev/null
+++ b/f.py
@@ -0,0 +1,26 @@
+from __future__ import print_function
+import sys
+
+N = int(sys.stdin.readline())
+K = int(sys.stdin.readline())
+
+D = {}; done = 0
+
+for line in sys.stdin:
+  C1, C2, P1, P2 = line.split(); C1, C2 = map(int, (C1, C2))
+  if P1 == P2: done += 1
+  D.setdefault(P1, set()).add(C1)
+  D.setdefault(P2, set()).add(C2)
+
+doubles = len([ k for k, v in D.iteritems() if len(v) == 2 ])
+singles = len([ k for k, v in D.iteritems() if len(v) == 1 ])
+
+left    = N - 2*doubles - singles
+answer  = doubles - done
+
+if singles == 0 and left == 2:
+  answer += 1
+elif singles == left:
+  answer += left
+
+print(answer)