answer will be infinite
$1 2 3 {\color{Red} 4 5 6 7 {\color{Red} 8}}$
here first packet lost is 4th and next packet lost is 8th but sender will not notice that is 8th is lost because as soon as sender did not get the ack of 4th packet he will start sending the packet again from 4th
that is
$4 5 6{\color{Red} 7} 8 9 $ $10$
now 7th packet will lost
so again sending
${\color{Red} 7} 8 9 $ $ 10$
again ${\color{Red} 7} 8 9 $ $ 10$ this process repeat forever