#R106C. [ABC106C] To Infinity
[ABC106C] To Infinity
Score: points
Problem Statement
Mr. Infinity has a string consisting of digits from 1 to 9. Each time the date changes, this string changes as follows:
- Each occurrence of
2in is replaced with22. Similarly, each3becomes333,4becomes4444,5becomes55555,6becomes666666,7becomes7777777,8becomes88888888and9becomes999999999.1remains as1.
For example, if is 1324, it becomes 1333224444 the next day, and it becomes 133333333322224444444444444444 the day after next.
You are interested in what the string looks like after days. What is the -th character from the left in the string after days?
Constraints
- is a string of length between and (inclusive).
- is an integer between and (inclusive).
- The length of the string after days is at least .
Input
Input is given from Standard Input in the following format:
Output
Print the -th character from the left in Mr. Infinity's string after days.
1214
4
2
The string changes as follows:
- Now:
1214 - After one day:
12214444 - After two days:
1222214444444444444444 - After three days:
12222222214444444444444444444444444444444444444444444444444444444444444444
The first five characters in the string after days is 12222. As , we should print the fourth character, 2.
3
157
3
The initial string is 3. The string after days consists only of 3.
299792458
9460730472580800
2