There are $2018$ boxes $C_1$, $C_2$, $C_3$,..,$C_{2018}$. The $n$-th box $C_n$ contains $n$ balls. A move consists of the following steps: a) Choose an integer $k$ greater than $1$ and choose $m$ a multiple of $k$. b) Take a ball from each of the consecutive boxes $C_{m-1}$, $C_m$, $C_{m+1}$ and move the $3$ balls to the box $C_{m+k}$. With these movements, what is the largest number of balls we can get in the box $2018$?
2018 Regional Olympiad of Mexico Northwest
Alicia and Bob take turns writing words on a blackboard. The rules are as follows: a) Any word that has been written cannot be rewritten. b) A player can only write a permutation of the previous word, or can simply simply remove one letter (whatever you want) from the previous word. c) The first person who cannot write another word loses. If Alice starts by typing the word ''Olympics" and Bob's next turn, who, do you think, has a winning strategy and what is it?
Let $ABC$ be an acute triangle orthocenter angle $H$. Let $\omega_1$ be the circle tangent to $BC$ at $B$ and passing through $H$ and $\omega_2$ the circle tangent to $BC$ at $C$ and passing through through $H$. A line $\ell$ passing through $H$ intersects the circles $\omega_1$ and $\omega_2$ at points $D$ and $E$, respectively (with $D$ and $E$ other than $H$). Lines $BD$ and $CE$ intersect at $F$, the lines $\ell$ and $AF$ intersect at $X$ and the circles $\omega_1$ and $\omega_2$ intersect at the points $P$ and $H$. Prove that the points $A, H, P$ and $X$ are still on the same circle.