Problem $2(10$ pts$).$ Estimate the compression strength of a folding carton with $4$ panels. For the carton's paperboard: the modulus of elasticity at MD and the modulus of elasticity at CD are $14l\frac{b}{i}{n}^2$ and $4l\frac{b}{i}{n}^2,$ respectively; the thickness is $1$ inch; and the short span compression strength is $40l\frac{b}{i}n.$