from exceptions import *
class neg(Exception): pass

while True:
    try:
        
        x = float(raw_input("enter an number"))
        if x < 0:
            raise neg, x
        print 1/x

        
    except ValueError, value:
         print "pleas give me  just numbers ",value
         
    except ZeroDivisionError, value:
        print " can't divid by zero ",value
    except neg, v:
        print " %s is not valide just positive numbers" % (v) 
    except:
        print "another one"
        raise 
    else:
        print "no exception"