diff --git a/cmd/pell.go b/cmd/pell.go
index 9124071..322a223 100644
--- a/cmd/pell.go
+++ b/cmd/pell.go
@@ -62,7 +62,7 @@ func pell(cmd *cobra.Command, args []string) {
 var pellCmd = &cobra.Command{
 	Use:   "pell",
 	Short: "Find solutions to a Pell equation",
-	Long:  `Find solutions to a Pell equation.`,
+	Long:  `Find solutions to a Pell equation x^2 - dy^2 = 1.`,
 	Run:   pell,
 }