7 temple 7 river puzzle

somewhere in the wonder land there are sequence of 7 Temples separated by 7 rivers,
Sequence is Temple, River, Temple, River…………
A man has to put equal number of flowers on every temple but the catch is as he crossed the river, remaining flowers will be doubled (2 times)

how many flowers should a man carry with him before entering into first temple so that till last river he has left with nothing?

Assume he took 5 flowers,
on first temple he drop 2, remaining is 3 as he crossed the river it will become 6, he put same number of flowers (i.e 2 flowers) 6-2=4 which again become twice in second river means 8…

I tried so many ways but cant get the answer?
Hope someone else come up with some good logical based answer