.htaccess query string redirect with same value

I want to redirect URLs with a query string to another query string using .htaccess

From: https://example.com/?smp=123456 (Any number after =)

To: https://example.com/?p=123456 (Same number as in From URL)

I tried following but it’s not working.

RewriteEngine on
RewriteCond %{QUERY_STRING} ^/?smp=([0-9]+)$ [NC]
RewriteRule ^$ https://www.example.com/?p=$ [R=301,L]

>Solution :

RewriteEngine On
RewriteCond %{QUERY_STRING} ^smp=([0-9]+)$ [NC]
RewriteRule ^$ /?p=%1 [R=301,L]