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