import math # Function to calculate sum of divisors def divisorsSum(n) : sum = 0 # Initialize sum of prime factors # Note that this loop runs till square # root of n i = 1 while i<= math.sqrt(n) : if (n % i == 0) : # If divisors are equal, take only one # of them if (n / i == i) : sum = sum + i else : # Otherwise take both sum = sum + i; sum = sum + (n / i) i = i + 1 return sum # Function to check Deficient Number def isDeficient(n) : # Check if sum(n) < 2 * n return (divisorsSum(n) < (2 * n)) # Driver program to test above function if ( isDeficient(12) ): print "YES" else : print "NO" if ( isDeficient(15) ) : print "YES" else : print "NO" # This Code is contributed by Nikita Tiwari