n,k=map(int, input().split())
s=input()
for i in range(len(s)):
    if i+1==k:
        print(chr(ord(s[i])+32),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(len(s)):
    if i+1==k:
        print(chr(ord(s[i])+32),end='')
    else:
        print(s[i],end='') i range(len(s)) range len(s) len s if i+1==k:
        print(chr(ord(s[i])+32),end='')
    else:
        print(s[i],end='') i+1==k i+1 i 1 k print(chr(ord(s[i])+32),end='') print chr(ord(s[i])+32) chr ord(s[i])+32 ord(s[i]) ord s[i] s i 32 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(len(s)):
    if i+1==k:
        print(chr(ord(s[i])+32),end='')
    else:
        print(s[i],end='')
