...

C.py

@@ -0,0 +1,7 @@
+from __future__ import print_function
+import sys
+x, y  = map(float, sys.stdin.readline().split())
+n     = float(sys.stdin.readline())
+for l,u,f in ( map(float, line.split()) for line in sys.stdin ):
+  y -= (u-l)*(1-f)
+print(x / y)