100 atcoder#ABC106C. [ABC106C] To Infinity

[ABC106C] To Infinity

Score: 300300 points

Problem Statement

Mr. Infinity has a string SS consisting of digits from 1 to 9. Each time the date changes, this string changes as follows:

  • Each occurrence of 2 in SS is replaced with 22. Similarly, each 3 becomes 333, 4 becomes 4444, 5 becomes 55555, 6 becomes 666666, 7 becomes 7777777, 8 becomes 88888888 and 9 becomes 999999999. 1 remains as 1.

For example, if SS 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 5×10155 \times 10^{15} days. What is the KK-th character from the left in the string after 5×10155 \times 10^{15} days?

Constraints

  • SS is a string of length between 11 and 100100 (inclusive).
  • KK is an integer between 11 and 101810^{18} (inclusive).
  • The length of the string after 5×10155 \times 10^{15} days is at least KK.

Input

Input is given from Standard Input in the following format:

SS

KK

Output

Print the KK-th character from the left in Mr. Infinity's string after 5×10155 \times 10^{15} days.

1214
4
2

The string SS 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 5×10155 \times 10^{15} days is 12222. As K=4K=4, we should print the fourth character, 2.

3
157
3

The initial string is 3. The string after 5×10155 \times 10^{15} days consists only of 3.

299792458
9460730472580800
2