Program for Armstrong Number. Check the given number is armstrong or not.
An Armstrong number is the sum of the nth powers of its digits is equal to the number.

It is also sometimes known as an n-narcissistic number, perfect digital invariant , or plus perfect number.

Armstrong Numbers:

Single Digit - 0, 1, 2, 3, 4, 5, 6, 7, 8, 9
ThreeDigit - 53, 370, 371, 407
Four Digits - 1634, 8208, 9474


Example: 153 = 1^3 + 5^3 + 3^3 = 3+125+27 =153