Discount in a Shop

One day, I was supposed to pay N Rs, but the shopkeeper gave me an unusual offer - he told me that I can remove one of the digits in the decimal representation of N and pay only the resulting price. 

I am trying to figure out the minimum price I have to pay if I choose the digit to remove optimally. Would you help me, please?

https://www.codechef.com/problems/DISCSHOP

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