When is Mary’s birthday?

M:Today is the twelfth of August. In another four days it will be my sister Mary’s birthday. We’11 have a party.Would you please come and join us, Jean?
W:What time will the party begin?
M:At twenty to two.
W:But my sister will come to see me from Shanghai at 1:20 that afternoon. I have to meet her at the station. So I’m afraid I’11 be late for the party.
M:That’s all right. Do come, please.
W:Sure!