Sample Input: 2 Sample Output: 97 Sample Input: 6 Sample Output: 999983 Explaination: TC 1: l=10^(2-1)=10 r=10^2-1=99 After checking in the sieve[] in decreasing order,the first time comes out to be 97 Time Complexity: O(limit log(log limit)),where limit is the size of the sieve[].This is the most optimal way to find out the required solution.