is the 21st single from the
Japanese idol group
Idoling!!!. It reached number 3 on M-ON! Countdown 100, number 2 on Music Station Single Ranking, and number 6 on Oricon Weekly Chart. Idoling!!! was divided into two groups. The main body of the group stayed with the name
Idoling!!!, while the other group was called
Idoling NEO. Idoling NEO consists of Idoling!!!'s new members, who just joined in August 2013, with addition of #23 Yuna Ito and #25 Kaoru Goto. Both groups released a single at the same time, with Idoling!!! releasing
Shout!!! as their 21st single under the
Pony Canyon label and Idoling NEO released
mero mero as their first single under the
Avex label. Both had to compete on the Oricon weekly chart for which group sold more than the other. The losing side will then receive a severe punishment.