What was the number of birds on that tree?

Once upon time, there was a bird that landed on a tree. The bird had noticed a group of birds on the same tree.

He said “hello hundred birds”.
One of the birds replied “we are not hundred, but if you sum the total number of us plus the same number of us plus the half of us plus a quarter of us plus yourself, only then the total number will be hundred birds”.

Then, the poor bird decided to run away.

What was the number of birds on that tree?

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