Nicolas is planning to send a package to his friend Anton, who is a stamp collector. To pay for the postage, Nicolas would like to cover the package with a large number of stamps. Suppose he has a collection of $5$-cent, $10$-cent, and $25$-cent stamps, with exactly $20$ of each type. What is the greatest number of stamps Nicolas can use to make exactly $7.10$ in postage?  
(Note: The amount $7.10$ corresponds to $7$ dollars and $10$ cents. One dollar is worth $100$ cents.)  
Fill in the blank with the greatest number of stamps: _______

Let's think step by step and output the final answer within \boxed{}.
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