How many 1.6 Gy fractions are required if the net effect is to be equivalent to 70 Gy delivered in 35 fractions?

Physics by Geoffrey

Radiation biology

A treatment consists of 46 Gy delivered in 23 daily fractions followed by a boost of 1.6 Gy per fraction delivered daily.

How many 1.6 Gy fractions are required if the net effect is to be equivalent to 70 Gy delivered in 35 fractions? Take alpha/beta= 3Gy