N, K = map(int, input().split())
S = input()

arr =[]
for i in range(N):
    if i+1 == K:
        arr.append(str.lower(S[i]))
    else:
        arr.append((S[i]))

print(*arr, sep='')
 N, K = map(int, input().split()) N map(int, input().split()) map int input().split() ().split () input split K S = input() S input() input arr =[] arr [] for i in range(N):
    if i+1 == K:
        arr.append(str.lower(S[i]))
    else:
        arr.append((S[i])) i range(N) range N if i+1 == K:
        arr.append(str.lower(S[i]))
    else:
        arr.append((S[i])) i+1 == K i+1 i 1 K arr.append(str.lower(S[i])) arr.append arr append str.lower(S[i]) str.lower str lower S[i] S i arr.append((S[i])) arr.append arr append S[i] S i print(*arr, sep='') print *arr arr sep='' sep '' K = map(int, input().split()) map(int, input().split()) K S = input() input() S N, K = map(int, input().split()) map(int, input().split()) N arr =[] [] arr
N, K = map(int, input().split())
S = input()

arr =[]
for i in range(N):
    if i+1 == K:
        arr.append(str.lower(S[i]))
    else:
        arr.append((S[i]))

print(*arr, sep='')

