n, k = map(int, input().split())
s = str(input())
answer = ''

for i in range(n):
    string = s[i]
    if i == k - 1:
        string = string.lower()

    answer += string

print(answer) n, k = map(int, input().split()) n map(int, input().split()) map int input().split() ().split () input split k s = str(input()) s str(input()) str input() input answer = '' answer '' for i in range(n):
    string = s[i]
    if i == k - 1:
        string = string.lower()

    answer += string i range(n) range n string = s[i] string s[i] s i if i == k - 1:
        string = string.lower()

     i == k - 1 i k - 1 k 1 string = string.lower() string string.lower() string.lower string lower answer += string answer string print(answer) print answer n, k = map(int, input().split()) map(int, input().split()) n string = s[i] s[i] string answer = '' '' answer string = string.lower() string.lower() string answer += string string answer k = map(int, input().split()) map(int, input().split()) k s = str(input()) str(input()) s
n, k = map(int, input().split())
s = str(input())
answer = ''

for i in range(n):
    string = s[i]
    if i == k - 1:
        string = string.lower()

    answer += string

print(answer)