ncr = ( n * ( n - 1 ) * ( n - 2 ) * ... . . ... ( n - r + 1 ) ) / ( r * ( r - 1 ) * ... * 1 )
while ( r > 0 ) : NEW_LINE INDENT numerator *= n NEW_LINE denominator *= r NEW_LINE n -= 1 NEW_LINE r -= 1 NEW_LINE DEDENT return ( numerator // denominator ) NEW_LINE