Power of Smile.

is a japanese 4-koma manga series written by Uro. It began serialisation in the April 2011 issue of Manga Time Kirara Carat.

The series was released under 5 volumes from September 2012 to September 2016.

Synopsis
Shinohana Mayu and Aoba Souma are childhood friends and enrolled in the same high school. There's energetic Mayu surrounded by her classmates with their unique personalities and Souma who always looks out for her. Join in their daily lives in this hybrid childhood friend-school life comedy!

(Source: Houbunsha via Anime Planet)