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

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

for i in range(n):
    if i == k-1:
        print(s[i].lower(),end = '')
    else:
        print(s[i] ,end ='')