Update cses-1716.mdx

changed n to m and m to n

solutions/gold/cses-1716.mdx

@@ -25,18 +25,18 @@ to count how many ways you can put the children between the apples.
 ## Explanation
 
 To get a more illustrative idea of the given problem, consider $n + m - 1$ white
-balls in a row. Of those $n + m - 1$ white balls, $m - 1$ are chosen to be
-colored black as separators, which gives us exactly $m$ segments of (possibly
+balls in a row. Of those $n + m - 1$ white balls, $n - 1$ are chosen to be
+colored black as separators, which gives us exactly $n$ segments of (possibly
 zero) white balls. There are
 
 $$
-\binom{n + m - 1}{m - 1}
+\binom{n + m - 1}{n - 1}
 $$
 
 ways to choose the balls to color black.
 
-The ways to color $m - 1$ balls black corresponds to the ways to distribute
-those $n$ apples to $m$ children, since the number of white balls in a segment
+The ways to color $n - 1$ balls black corresponds to the ways to distribute
+those $m$ apples to $n$ children, since the number of white balls in a segment
 corresponds to the number of apples given to a child.
 
 <Info title="Stars and bars">