diff --git a/13/fraction.md b/13/fraction.md
index db4c1ed..923a6e1 100644
--- a/13/fraction.md
+++ b/13/fraction.md
@@ -27,7 +27,10 @@ class Fraction:
 			self.up = self.up // divisor # znena sebe sama
 			self.down = self.down // divisor # a zase
 
-			self.base() # rekurze, slo by to udelat i snadneji
+		if self.up < 0 and self.down < 0:
+			self.up = -self.up
+			self.down = -self.down
+
 
 	# scitani zlomku
 	def add(self, other):
diff --git a/13/fraction.py b/13/fraction.py
index f528f46..5df2ac6 100644
--- a/13/fraction.py
+++ b/13/fraction.py
@@ -25,7 +25,10 @@ class Fraction:
 			self.up = self.up // divisor # znena sebe sama
 			self.down = self.down // divisor # a zase
 
-			self.base() # rekurze, slo by to udelat i snadneji
+		if self.up < 0 and self.down < 0:
+			self.up = -self.up
+			self.down = -self.down
+
 
 	# scitani zlomku
 	def add(self, other):