It is enough to get an answer to the question "How many coins are there in total in the wallets with odd numbers?" Indeed, if the answer to it is " $1600+n$ " ( $n>0$ ), then the coins were moved from the wallet with an even number, to the right of which there were exactly $n$ wallets with odd numbers - that is, from the ( $2 n+1$ )-th wallet from the right. If, however, the answer to it is " $1600-n$ " ( $n>0$ ), then the coins were moved from the wallet with an odd number, to the right of which there were exactly $n$ wallets with even numbers - that is, from the $2 n$-th wallet from the right.

## Answer

In one question.

## Problem


Shapovalov A.V.
In a row from left to right, there are 31 wallets, each containing 100 coins. From one of the wallets, some coins were moved: one coin to each of the wallets to the right of it. With one question, you can find out the total number of coins in any set of wallets. What is the minimum number of questions needed to reliably determine the "lightened" wallet?