Hello codeforces :D

I was trying to solve this problem

and I got TLE , I tried to solve it using DP.

my approach for this problem , first I find how many 369 are there in the interval [ 1 , B ] , let this value be right

then I find how many 369 are there in the interval [ 1 , A ] , let this value be left

my final answer will be right — left , if A is not 369 number

else it will be : right — left + 1

here is my code

can I do some pre calculations to avoid TLE ?

thank in advance :D