import re
a = input()
b = input()
c = re.search('(\d+)\s(\d+)', a)
d = int(c.group(1))
e = int(c.group(2))
result = ''
for n in range(d):
    if n == e - 1:
        r = str(b[n]).lower()
        result += r
    else:
        result += b[n]
print(result) import re re a = input() a input() input b = input() b input() input c = re.search('(\d+)\s(\d+)', a) c re.search('(\d+)\s(\d+)', a) re.search re search '(\d+)\s(\d+)' a d = int(c.group(1)) d int(c.group(1)) int c.group(1) c.group c group 1 e = int(c.group(2)) e int(c.group(2)) int c.group(2) c.group c group 2 result = '' result '' for n in range(d):
    if n == e - 1:
        r = str(b[n]).lower()
        result += r
    else:
        result += b[n] n range(d) range d if n == e - 1:
        r = str(b[n]).lower()
        result += r
    else:
        result += b[n] n == e - 1 n e - 1 e 1 r = str(b[n]).lower() r str(b[n]).lower() (b[n]).lower (b[n]) str b[n] b n lower result += r result r result += b[n] result b[n] b n print(result) print result b = input() input() b c = re.search('(\d+)\s(\d+)', a) re.search('(\d+)\s(\d+)', a) c result = '' '' result a = input() input() a result += r r result r = str(b[n]).lower() str(b[n]).lower() r d = int(c.group(1)) int(c.group(1)) d e = int(c.group(2)) int(c.group(2)) e result += b[n] b[n] result
import re
a = input()
b = input()
c = re.search('(\d+)\s(\d+)', a)
d = int(c.group(1))
e = int(c.group(2))
result = ''
for n in range(d):
    if n == e - 1:
        r = str(b[n]).lower()
        result += r
    else:
        result += b[n]
print(result)
