Shakuntala Devi was undoubtedly the most brilliant arithmetic mental calculator of all time. In 1977 she mentally calculated the 23^{rd} root of a 201 digit number in a mere 50 seconds. She toured the world showing how she could do calculations faster than they could be entered into and solved by the computers of the day.

The problem for you is much simpler: Evaluate (without using a calculator) the 20^{th} root of the 11 digit number consisting of 1 followed by all zeros.

Author: Leslie Green