Runs on billions of devices... Slowly

Solve at least 50 problems as official contestant in Java

vidyut_11, first achieved on March 5, 2017

Goran11, first achieved on Dec. 19, 2016

wolfib1, first achieved on Nov. 27, 2016

Quvondiq_Otajonov1, first achieved on Nov. 11, 2013

kraskevich1, first achieved on May 3, 2015

afterlight1, first achieved on Dec. 8, 2013

pvtuan101, first achieved on Sept. 4, 2017

pius_881, first achieved on June 20, 2011

a3636tako1, first achieved on June 29, 2016

Sagar_Savaliya1, first achieved on Jan. 31, 2017

shambala221, first achieved on March 16, 2016

alex7001, first achieved on Sept. 16, 2015

Dey1, first achieved on March 11, 2017

wolf30011, first achieved on Oct. 3, 2015

Izaron1, first achieved on Feb. 20, 2016

kubusgol1, first achieved on March 2, 2015

OmarRadwan1, first achieved on May 11, 2017

waleed1, first achieved on April 14, 2015

xDister1, first achieved on Dec. 30, 2016

Gantz1, first achieved on April 24, 2012