import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Arrays;
import java.util.List;

class Main {

    public static void main(String[] args) throws Exception {

        try {

            BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

            List<String> inputIndex = Arrays.asList(br.readLine().split(" "));
            StringBuilder inputString = new StringBuilder(br.readLine());

            int lowerIndex = Integer.parseInt(inputIndex.get(1));
            inputString.replace(lowerIndex - 1, lowerIndex,  inputString.substring(lowerIndex - 1, lowerIndex).toLowerCase());

            System.out.println(inputString);
        } catch (IOException | NumberFormatException e) {
            e.printStackTrace();
            System.exit(0);
        } catch (final Exception e) {
            e.printStackTrace();
            System.exit(0);
        }
    }
} import java.io.BufferedReader; BufferedReader java.io import java.io.IOException; IOException java.io import java.io.InputStreamReader; InputStreamReader java.io import java.util.Arrays; Arrays java.util import java.util.List; List java.util class Main {

    public static void main(String[] args) throws Exception {

        try {

            BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

            List<String> inputIndex = Arrays.asList(br.readLine().split(" "));
            StringBuilder inputString = new StringBuilder(br.readLine());

            int lowerIndex = Integer.parseInt(inputIndex.get(1));
            inputString.replace(lowerIndex - 1, lowerIndex,  inputString.substring(lowerIndex - 1, lowerIndex).toLowerCase());

            System.out.println(inputString);
        } catch (IOException | NumberFormatException e) {
            e.printStackTrace();
            System.exit(0);
        } catch (final Exception e) {
            e.printStackTrace();
            System.exit(0);
        }
    }
} Main public static void main(String[] args) throws Exception {

        try {

            BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

            List<String> inputIndex = Arrays.asList(br.readLine().split(" "));
            StringBuilder inputString = new StringBuilder(br.readLine());

            int lowerIndex = Integer.parseInt(inputIndex.get(1));
            inputString.replace(lowerIndex - 1, lowerIndex,  inputString.substring(lowerIndex - 1, lowerIndex).toLowerCase());

            System.out.println(inputString);
        } catch (IOException | NumberFormatException e) {
            e.printStackTrace();
            System.exit(0);
        } catch (final Exception e) {
            e.printStackTrace();
            System.exit(0);
        }
    } main {

        try {

            BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

            List<String> inputIndex = Arrays.asList(br.readLine().split(" "));
            StringBuilder inputString = new StringBuilder(br.readLine());

            int lowerIndex = Integer.parseInt(inputIndex.get(1));
            inputString.replace(lowerIndex - 1, lowerIndex,  inputString.substring(lowerIndex - 1, lowerIndex).toLowerCase());

            System.out.println(inputString);
        } catch (IOException | NumberFormatException e) {
            e.printStackTrace();
            System.exit(0);
        } catch (final Exception e) {
            e.printStackTrace();
            System.exit(0);
        }
    } try {

            BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

            List<String> inputIndex = Arrays.asList(br.readLine().split(" "));
            StringBuilder inputString = new StringBuilder(br.readLine());

            int lowerIndex = Integer.parseInt(inputIndex.get(1));
            inputString.replace(lowerIndex - 1, lowerIndex,  inputString.substring(lowerIndex - 1, lowerIndex).toLowerCase());

            System.out.println(inputString);
        } catch (IOException | NumberFormatException e) {
            e.printStackTrace();
            System.exit(0);
        } catch (final Exception e) {
            e.printStackTrace();
            System.exit(0);
        } catch (IOException | NumberFormatException e) {
            e.printStackTrace();
            System.exit(0);
        } IOException | NumberFormatException e {
            e.printStackTrace();
            System.exit(0);
        } e.printStackTrace() e.printStackTrace e System.exit(0) System.exit System 0 catch (final Exception e) {
            e.printStackTrace();
            System.exit(0);
        } final Exception e {
            e.printStackTrace();
            System.exit(0);
        } e.printStackTrace() e.printStackTrace e System.exit(0) System.exit System 0 {

            BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

            List<String> inputIndex = Arrays.asList(br.readLine().split(" "));
            StringBuilder inputString = new StringBuilder(br.readLine());

            int lowerIndex = Integer.parseInt(inputIndex.get(1));
            inputString.replace(lowerIndex - 1, lowerIndex,  inputString.substring(lowerIndex - 1, lowerIndex).toLowerCase());

            System.out.println(inputString);
        } BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); br new BufferedReader(new InputStreamReader(System.in)) List<String> inputIndex = Arrays.asList(br.readLine().split(" ")); inputIndex Arrays.asList(br.readLine().split(" ")) Arrays.asList Arrays br.readLine().split(" ") br.readLine().split br.readLine() br.readLine br " " StringBuilder inputString = new StringBuilder(br.readLine()); inputString new StringBuilder(br.readLine()) int lowerIndex = Integer.parseInt(inputIndex.get(1)); lowerIndex Integer.parseInt(inputIndex.get(1)) Integer.parseInt Integer inputIndex.get(1) inputIndex.get inputIndex 1 inputString.replace(lowerIndex - 1, lowerIndex,  inputString.substring(lowerIndex - 1, lowerIndex).toLowerCase()) inputString.replace inputString lowerIndex - 1 lowerIndex 1 lowerIndex inputString.substring(lowerIndex - 1, lowerIndex).toLowerCase() inputString.substring(lowerIndex - 1, lowerIndex).toLowerCase inputString.substring(lowerIndex - 1, lowerIndex) inputString.substring inputString lowerIndex - 1 lowerIndex 1 lowerIndex System.out.println(inputString) System.out.println System.out System System.out inputString String[] args args
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Arrays;
import java.util.List;

class Main {

    public static void main(String[] args) throws Exception {

        try {

            BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

            List<String> inputIndex = Arrays.asList(br.readLine().split(" "));
            StringBuilder inputString = new StringBuilder(br.readLine());

            int lowerIndex = Integer.parseInt(inputIndex.get(1));
            inputString.replace(lowerIndex - 1, lowerIndex,  inputString.substring(lowerIndex - 1, lowerIndex).toLowerCase());

            System.out.println(inputString);
        } catch (IOException | NumberFormatException e) {
            e.printStackTrace();
            System.exit(0);
        } catch (final Exception e) {
            e.printStackTrace();
            System.exit(0);
        }
    }
}