Freshman's Product (noch nicht übersetzt)
Problem 778
If a,b are two nonnegative integers with decimal representations a=(…a2a1a0) and b=(…b2b1b0) respectively, then the freshman's product of a and b, denoted a⊠b, is the integer c with decimal representation c=(…c2c1c0) such that ci is the last digit of ai⋅bi.
For example, 234⊠765=480.
Let F(R,M) be the sum of x1⊠⋯⊠xR for all sequences of integers (x1,…,xR) with 0≤xi≤M.
For example, F(2,7)=204, and F(23,76)≡5870548(mod1000000009).
Find F(234567,765432), give your answer modulo 1000000009