Score: 300 points
Mr. Infinity has a string S consisting of digits from 1
to 9
. Each time the date changes, this string changes as follows:
2
in S 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 S 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 \times 10^{15} days. What is the K-th character from the left in the string after 5 \times 10^{15} days?
Input is given from Standard Input in the following format:
S K
Print the K-th character from the left in Mr. Infinity's string after 5 \times 10^{15} days.
1214 4
2
The string S changes as follows:
1214
12214444
1222214444444444444444
12222222214444444444444444444444444444444444444444444444444444444444444444
The first five characters in the string after 5 \times 10^{15} days is 12222
. As K=4, we should print the fourth character, 2
.
3 157
3
The initial string is 3
. The string after 5 \times 10^{15} days consists only of 3
.
299792458 9460730472580800
2