CF2045B ICPC Square

ICPC Square is a hotel provided by the ICPC Committee for the accommodation of the participants. It consists of $ N $ floors (numbered from $ 1 $ to $ N $ ). This hotel has a very unique elevator. If a person is currently at floor $ x $ , by riding the elevator once, they can go to floor $ y $ if and only if $ y $ is a multiple of $ x $ and $ y - x \leq D $ . You are currently at floor $ S $ . You want to go to the highest possible floor by riding the elevator zero or more times. Determine the highest floor you can reach.

A single line consisting of three integers $ N $ $ D $ $ S $ ( $ 2 \leq N \leq 10^{12}; 1 \leq D \leq N - 1; 1 \leq S \leq N $ ).

Output a single integer representing the highest floor you can reach by riding the elevator zero or more times.

Explanation for the sample input/output #1 First, ride the elevator from floor $ 3 $ to floor $ 15 $ . This is possible because $ 15 $ is a multiple of $ 3 $ and $ 15 - 3 \leq 35 $ . Then, ride the elevator from floor $ 15 $ to floor $ 30 $ . This is possible because $ 30 $ is a multiple of $ 15 $ and $ 30 - 15 \leq 35 $ . Finally, ride the elevator from floor $ 30 $ to floor $ 60 $ . This is possible because $ 60 $ is a multiple of $ 30 $ and $ 60 - 30 \leq 35 $ .