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