米粒 こめつぶ うま やしじゃないです
kometsubūma koyashijanaidesu

Noun
Desu Copula
Negation Auxiliary

The polite negative form of 米粒馬肥やし

1. It's not like a single grain of rice makes a horse fat.; It's not a small effort.

Negative
Polite
Casual Register