import random
import sys
def lb(x):
    r = 1
    while x&r == 0:
        r = r*2
    return r
def pos(l, v):
    f = lambda x : lb(x-v) if x != v else 2**420
    k = sorted(l, key=f)
    for i in xrange(len(k)-1):
        r, s, t = abs(k[i+1]-k[i]), f(k[i]), f(k[i+1])
        if r % (2*s) != s or r > 2*t-s:
            return False
    return True
l = map(int,raw_input())
l.sort()
for i in xrange(1,len(l)):
    if l[i] == l[i-1]:
        print 'Invalid'
        sys.exit(0)
if pos(l,l[0]) or pos(l,l[-1]):
    print 'Valid'
else:
    print 'Invalid'