diff --git a/ex3/ex3_nn.py b/ex3/ex3_nn.py
index 5574b1d..d6f55b9 100644
--- a/ex3/ex3_nn.py
+++ b/ex3/ex3_nn.py
@@ -74,7 +74,7 @@
 
 pred = predict(Theta1, Theta2, X)
 
-print('Training Set Accuracy: %f\n', np.mean(np.double(pred == np.squeeze(y))) * 100)
+print('Training Set Accuracy: %f\n' % (np.mean(np.double(pred == np.squeeze(y))) * 100))
 
 input('Program paused. Press Enter to continue...')