diff --git a/examples/ex18.py b/examples/ex18.py
index 11e67b3b9..d04153cec 100644
--- a/examples/ex18.py
+++ b/examples/ex18.py
@@ -57,7 +57,7 @@ def unit_rotation(v, dv, ddv, w):
     
     M, Psi = ib.refinterp(psi, 3)
     Psi0 = max(Psi)
-    print('phi0 = {} (cf. exact = 1/64 = {})'.format(Psi0, 1/64))
+    print('max psi = {} (cf. exact = 1/64 = {})'.format(Psi0, 1/64))
 
     ax = mesh.draw()
     fig = ax.get_figure()