--- Lib/fractions.py	2014-08-22 18:59:30.623831217 +0200
+++ Lib/fractions.py	2014-09-22 20:53:50.524802173 +0200
@@ -104,7 +104,12 @@
         self = super(Fraction, cls).__new__(cls)
 
         if denominator is None:
-            if isinstance(numerator, numbers.Rational):
+            if type(numerator) is int:
+                self._numerator = numerator
+                self._denominator = 1
+                return self
+
+            elif isinstance(numerator, numbers.Rational):
                 self._numerator = numerator.numerator
                 self._denominator = numerator.denominator
                 return self
@@ -153,6 +158,9 @@
                 raise TypeError("argument should be a string "
                                 "or a Rational instance")
 
+        elif type(numerator) is int and type(denominator) is int:
+            pass  # *very* normal case
+
         elif (isinstance(numerator, numbers.Rational) and
             isinstance(denominator, numbers.Rational)):
             numerator, denominator = (