n, k = map(int,input().split())
s = input()
result_s = ''
a = 0

for s in list(s):
    a += 1
    if a==k:
        s = s.lower()
    result_s += s

print(result_s) n, k = map(int,input().split()) n map(int,input().split()) map int input().split() ().split () input split k s = input() s input() input result_s = '' result_s '' a = 0 a 0 for s in list(s):
    a += 1
    if a==k:
        s = s.lower()
    result_s += s s list(s) list s a += 1 a 1 if a==k:
        s = s.lower()
     a==k a k s = s.lower() s s.lower() s.lower s lower result_s += s result_s s print(result_s) print result_s s = input() input() s result_s += s s result_s s = s.lower() s.lower() s n, k = map(int,input().split()) map(int,input().split()) n a = 0 0 a k = map(int,input().split()) map(int,input().split()) k result_s = '' '' result_s a += 1 1 a
n, k = map(int,input().split())
s = input()
result_s = ''
a = 0

for s in list(s):
    a += 1
    if a==k:
        s = s.lower()
    result_s += s

print(result_s)