HMMT 2015 U33

Let $N$ denote the sum of the decimal digits of $\binom{1000}{100}$. Estimate the value of $N$. If your answer is a positive integer $A$ written fully in decimal notation (for example, 521495223 ), your score will be the greatest integer not exceeding $25 \cdot(0.99)^{|A-N|}$. Otherwise, your score will be zero.