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

new = ""
for i in range(len(s)):
    if i == k-1:
        new += s[i].lower()
    else:
        new += s[i]

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

new = ""
for i in range(len(s)):
    if i == k-1:
        new += s[i].lower()
    else:
        new += s[i]

print(new)