string starting with 1 - 8 places 1 place fixed .7 places have 2 choices . 2^7=128
ending with 00- 8 places 2 fixed. =2^6=64
common strings will be there that have been counted twice are . starting with 1 and ending with 00. such number of string will be .
fix 3 position rest have 2 choices=32
total = 128+64-32=160