def sus5(n):
if n == 0: return 2
if n == 1: return 3
if n == 2: return 4
return sus5(n-3)*2+sus5(n-2)+sus5(n-1)
print(sus5(7))
ZGVmIHN1czUobik6CglpZiBuID09IDA6IHJldHVybiAyCglpZiBuID09IDE6IHJldHVybiAzCglpZiBuID09IDI6IHJldHVybiA0CglyZXR1cm4gc3VzNShuLTMpKjIrc3VzNShuLTIpK3N1czUobi0xKSAKcHJpbnQoc3VzNSg3KSk=