Question 34
Nonnegative integers $a_1, \dots, a_{100}$ satisfy the inequality
$$
a_1 \cdot (a_1-1) \cdot \dots \cdot (a_1-20) + a_2 \cdot (a_2-1) \cdot \dots \cdot (a_2-20) + \dots + a_{100} \cdot (a_{100}-1) \cdot \dots \cdot (a_{100}-20) \le 100 \cdot 99 \cdot 98 \cdot \dots \cdot 79.
$$
Prove that $a_1 + \dots + a_{100} \le 9900$.
$$
a_1 \cdot (a_1-1) \cdot \dots \cdot (a_1-20) + a_2 \cdot (a_2-1) \cdot \dots \cdot (a_2-20) + \dots + a_{100} \cdot (a_{100}-1) \cdot \dots \cdot (a_{100}-20) \le 100 \cdot 99 \cdot 98 \cdot \dots \cdot 79.
$$
Prove that $a_1 + \dots + a_{100} \le 9900$.