だい さん しゅ郵便 ゆうびん ぶつではありません
daisanshuyūbimbutsudewārimasen

Noun
Desu Copula
Negation Auxiliary

The polite negative form of 第三種郵便物

1. It is not the third kind of mail.; It is not a third-class mailing.

Negative
Polite
Formal Register