known=raw_input("What is known? slant side or height: ")
known=known.lower()
if known=="slant side":
    from math import sqrt
    r=raw_input("Input radius of the base circle: ")
    l=raw_input("Input length of slant side: ")
    if not r.isalpha() and not l.isalpha():
        r=float(r)
        l=float(l)
        height=l**2-r**2
        h=sqrt(height)
        h=float(h)
        cylinder=pi*h*r**2
        volume=cylinder/3
        print "Volume of the given cone is %s unit^3" %(volume)
    else:
        print "Please enter valid values..."
elif known=="height":
    h=raw_input("Input height: ")
    r=raw_input("Input radius of base circle: ")
    if not h.isalpha() and not r.isalpha():
        h=float(h)
        r=float(r)
        cylinder=pi*h*r**2
        volume=cylinder/3
        print "Volume of the given cylinder is %s unit^3" %(volume)
    else:
        print "Please enter valid values..."
else:
    print "Invalid data..."