n,k=[int(x) for x in input().split()]
s=input()
 
ans=s[:k-1]+s[k-1].lower()+s[k:]

print(ans) int(x) for x in input().split() for x in input().split() x input().split() ().split () input split for x in input().split() int(x) int x n,k=[int(x) for x in input().split()] n [int(x) for x in input().split()] k s=input() s input() input ans=s[:k-1]+s[k-1].lower()+s[k:] ans s[:k-1]+s[k-1].lower()+s[k:] s[:k-1]+s[k-1].lower() s[:k-1] s :k-1 k-1 k 1 s[k-1].lower() [k-1].lower [k-1] s k-1 k 1 lower s[k:] s k: k print(ans) print ans k=[int(x) for x in input().split()] [int(x) for x in input().split()] k s=input() input() s ans=s[:k-1]+s[k-1].lower()+s[k:] s[:k-1]+s[k-1].lower()+s[k:] ans n,k=[int(x) for x in input().split()] [int(x) for x in input().split()] n
n,k=[int(x) for x in input().split()]
s=input()
 
ans=s[:k-1]+s[k-1].lower()+s[k:]

print(ans)