import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int N = sc.nextInt();
        int K = sc.nextInt()-1;
        String S = sc.next();
        char[] C = S.toCharArray();
        char targetChar = C[K];

        String targetString = String.valueOf(targetChar);
        targetString = targetString.toLowerCase();

        char[] tmp = targetString.toCharArray();
        C[K] = tmp[0];

        for (char c : C) {
            System.out.print(c);
        }
    }
} import java.util.Scanner; Scanner java.util public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int N = sc.nextInt();
        int K = sc.nextInt()-1;
        String S = sc.next();
        char[] C = S.toCharArray();
        char targetChar = C[K];

        String targetString = String.valueOf(targetChar);
        targetString = targetString.toLowerCase();

        char[] tmp = targetString.toCharArray();
        C[K] = tmp[0];

        for (char c : C) {
            System.out.print(c);
        }
    }
} Main public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int N = sc.nextInt();
        int K = sc.nextInt()-1;
        String S = sc.next();
        char[] C = S.toCharArray();
        char targetChar = C[K];

        String targetString = String.valueOf(targetChar);
        targetString = targetString.toLowerCase();

        char[] tmp = targetString.toCharArray();
        C[K] = tmp[0];

        for (char c : C) {
            System.out.print(c);
        }
    } main {
        Scanner sc = new Scanner(System.in);

        int N = sc.nextInt();
        int K = sc.nextInt()-1;
        String S = sc.next();
        char[] C = S.toCharArray();
        char targetChar = C[K];

        String targetString = String.valueOf(targetChar);
        targetString = targetString.toLowerCase();

        char[] tmp = targetString.toCharArray();
        C[K] = tmp[0];

        for (char c : C) {
            System.out.print(c);
        }
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int N = sc.nextInt(); N sc.nextInt() sc.nextInt sc int K = sc.nextInt()-1; K sc.nextInt()-1 sc.nextInt() sc.nextInt sc 1 String S = sc.next(); S sc.next() sc.next sc char[] C = S.toCharArray(); C S.toCharArray() S.toCharArray S char targetChar = C[K]; targetChar C[K] C K String targetString = String.valueOf(targetChar); targetString String.valueOf(targetChar) String.valueOf String targetChar targetString = targetString.toLowerCase() targetString targetString.toLowerCase() targetString.toLowerCase targetString char[] tmp = targetString.toCharArray(); tmp targetString.toCharArray() targetString.toCharArray targetString C[K] = tmp[0] C[K] C K tmp[0] tmp 0 for (char c : C) {
            System.out.print(c);
        } char c C {
            System.out.print(c);
        } {
            System.out.print(c);
        } System.out.print(c) System.out.print System.out System System.out c String[] args args public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int N = sc.nextInt();
        int K = sc.nextInt()-1;
        String S = sc.next();
        char[] C = S.toCharArray();
        char targetChar = C[K];

        String targetString = String.valueOf(targetChar);
        targetString = targetString.toLowerCase();

        char[] tmp = targetString.toCharArray();
        C[K] = tmp[0];

        for (char c : C) {
            System.out.print(c);
        }
    }
} public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int N = sc.nextInt();
        int K = sc.nextInt()-1;
        String S = sc.next();
        char[] C = S.toCharArray();
        char targetChar = C[K];

        String targetString = String.valueOf(targetChar);
        targetString = targetString.toLowerCase();

        char[] tmp = targetString.toCharArray();
        C[K] = tmp[0];

        for (char c : C) {
            System.out.print(c);
        }
    }
} Main
import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int N = sc.nextInt();
        int K = sc.nextInt()-1;
        String S = sc.next();
        char[] C = S.toCharArray();
        char targetChar = C[K];

        String targetString = String.valueOf(targetChar);
        targetString = targetString.toLowerCase();

        char[] tmp = targetString.toCharArray();
        C[K] = tmp[0];

        for (char c : C) {
            System.out.print(c);
        }
    }
}
