CHICAGO (CBS) — Thousands of Chicago students essentially told Mayor Rahm Emanuel to go jump in a lake — a very cold lake, to boot — when they hit the books this summer.

The kids took up the mayor’s challenge to read more books this summer, and now he will have live up to his end of the bargain and take part in the annual Polar Plunge, which raises money for the Special Olympics.

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The mayor, Library Commissioner Brian Bannon, and former Chicago Bears defensive lineman Israel Idonije – a library board member – had challenged kids in the “Rahm’s Readers” program to read a combined total of 2 million books this summer.

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The kids beat that goal, with 2.1 million books read this summer.

“I’m ruing the day that I thought I would challenge the children of the city of Chicago. They did it,” Emanuel said Thursday.

It helped that more kids took part in this summer’s reading program. Last year, there were about 63,000 kids in the program; this year, the number jumped to more than 71,000.

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The Polar Plunge is held every March in Chicago, when Lake Michigan is usually about 42 degrees.