Add/Update leads into Marketo using batchsize of 300

I would like to pass 300 leads in one API call. I am able to pass one record and it is working fine.

How do i achieve this ?

This is the sample request.
{
“action”:“createOnly”,
“lookupField”:“email”,
“input”:[
{
“email":"kjashaedd-1@klooblept.com”,
“firstName”:“Kataldar-1”,
“postalCode”:“04828”
},
{
“email":"kjashaedd-2@klooblept.com”,
“firstName”:“Kataldar-2”,
“postalCode”:“04828”
},
{
“email":"kjashaedd-3@klooblept.com”,
“firstName”:“Kataldar-3”,
“postalCode”:“04828”
}
]
}