Algorithm Analysis

The input number can be negative. The number n is two-digit if $-99{\le }_n\le -10$ or $10{\le }_n\le 99$.

Algorithm Implementation

Read the input number n.

scanf("%d", &n);

Output the answer.

if ((n > -100 && n < -9) || (n > 9 && n < 100)) puts("Ok");
else puts("No");