exhibit 2. 1 note : schedules and exhibits to the pst purchase agreement are omitted from this exhibit 2. 1. the following schedules and exhibits have been omitted : appendix a ( accredited investor definition ), exhibit a ( second amended and restatement of quotaholders ’ agreement ), exhibit b ( form of investors ’ rights agreement ) and schedule 4. 5, 4. 6, 4. 7, 4. 8, 4. 9 ( a ), 4. 10 ( a ), 4. 10 ( b ), 4. 11, 4. 12 ( a ), 4. 12 ( b ), 4. 12 ( c ), 4. 12 ( d ), 4. 12 ( e ), 4. 12 ( f ), 4. 13, 4. 15, 4. 16, 4. 18 ( a ), 4. 19, 7. 2, 7. 7, and 11. 2. the company agrees to furnish supplementally a copy of any omitted schedule or exhibit to the commission upon request. agreement for the purchase and sale of shares of pst eletronica s. a. the parties to this agreement for the purchase and sale of shares of pst eletronica s. a. ( the “ agreement ” ), are as follows : ( 1 ) marcos ferretti ( “ ferretti ” ), brazilian citizen, married, electrical engineer, with office at rua jose alexandrino palazzo, 481, in the city of campinas, state of sao paulo, holder of identity card rg no. xxxx, individual taxpayers ’ registration ( cpf / mf ) no. xxxx ; and ( 2 ) adriana campos de cerqueira leite ( “ adriana leite ” ), brazilian citizen, divorced, psychologist, holder of the identity card rg no. xxxx, individual taxpayer registration ( cpf / mf ) no. xxxx, resident and domiciled in the city of campinas, state of sao paulo, at alameda bauinias, no. 350, condominio chacaras alto de nova campinas. ( ferretti and adriana leite are each a “ seller ” and are collectively, the “ sellers ” ) ; and ( 3 ) alphabet do brasil ltda., a limited business company, with head office at estrada da telebras - unicamp km 0, 9, w / n