def na10(dana):
pom= 0
for i in range(len(dana)):
x = int(dana[- i - 1])
pom = pom + x * 2 ** i
return pom# your code goes here
print(na10("101010"))
ZGVmIG5hMTAoZGFuYSk6Cglwb209IDAKCWZvciBpIGluIHJhbmdlKGxlbihkYW5hKSk6CgkJeCA9IGludChkYW5hWy0gaSAtIDFdKQoJCXBvbSA9IHBvbSArIHggKiAyICoqIGkKCXJldHVybiAgcG9tIyB5b3VyIGNvZGUgZ29lcyBoZXJlCnByaW50KG5hMTAoIjEwMTAxMCIpKQo=