98. There are 3 integers $\mathrm{A}, \mathrm{B}, \mathrm{C}$, if 5 times $\mathrm{B}$ is 4 times the difference between $\mathrm{A}$ and 1, 5 times $\mathrm{C}$ is 4 times the difference between $\mathrm{B}$ and 1, then the smallest value of $\mathrm{A}$ is $\qquad$.
answer: 21