n, k = map(int, input().split())
s = input()
sl = []
for i in range(len(s)):
    sl.append(s[i])

Al = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
al = 'abcdefghijklmnopqrstuvwxyz'

for i in range(len(Al)):
    if sl[k-1] == Al[i]:
        sl[k-1] = (al[i])


print(''.join(sl)) n, k = map(int, input().split()) n map(int, input().split()) map int input().split() ().split () input split k s = input() s input() input sl = [] sl [] for i in range(len(s)):
    sl.append(s[i]) i range(len(s)) range len(s) len s sl.append(s[i]) sl.append sl append s[i] s i Al = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ' Al 'ABCDEFGHIJKLMNOPQRSTUVWXYZ' al = 'abcdefghijklmnopqrstuvwxyz' al 'abcdefghijklmnopqrstuvwxyz' for i in range(len(Al)):
    if sl[k-1] == Al[i]:
        sl[k-1] = (al[i]) i range(len(Al)) range len(Al) len Al if sl[k-1] == Al[i]:
        sl[k-1] = (al[i]) sl[k-1] == Al[i] sl[k-1] sl k-1 k 1 Al[i] Al i sl[k-1] = (al[i]) sl[k-1] sl k-1 k 1 al[i] al i print(''.join(sl)) print ''.join(sl) ''.join '' join sl Al = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ' 'ABCDEFGHIJKLMNOPQRSTUVWXYZ' Al k = map(int, input().split()) map(int, input().split()) k sl = [] [] sl al = 'abcdefghijklmnopqrstuvwxyz' 'abcdefghijklmnopqrstuvwxyz' al n, k = map(int, input().split()) map(int, input().split()) n s = input() input() s
n, k = map(int, input().split())
s = input()
sl = []
for i in range(len(s)):
    sl.append(s[i])

Al = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
al = 'abcdefghijklmnopqrstuvwxyz'

for i in range(len(Al)):
    if sl[k-1] == Al[i]:
        sl[k-1] = (al[i])


print(''.join(sl))