Equate XY

You have with you four positive integers $X, Y, Z,$ and $C$. You'd like to make $X$ equal to $Y$. To achieve that, you can perform the following types of operations: - Pay one coin, and either increase or decrease $Z$ by $1$. The decrease operation can only be done if $Z \gt 1$ initially, i.e. it's not allowed to make $Z$ reach $0$. - Pay $C$ coins, and do one of the following: - Replace $