Function to find the leftmost unset bit in a number .
def find_leftmost_unsetbit ( n ) : NEW_LINE INDENT ind = - 1 ; NEW_LINE i = 1 ; NEW_LINE while ( n ) : NEW_LINE INDENT if ( ( n % 2 ) != 1 ) : NEW_LINE INDENT ind = i ; NEW_LINE DEDENT i += 1 ; NEW_LINE n >>= 1 ; NEW_LINE DEDENT return ind ; NEW_LINE DEDENT