uppertolower

import java.util.Scanner;

public class uppertolower {

	public static void main (String [] args) {

		Scanner input = new Scanner(System.in);

      char start = input.next().charAt(0);

		char end = stringlol(start);

		System.out.println(end); 

	}

	public static char stringlol(char start){
      char end;

if (Character.isLowerCase(start)) {
   end = start;
}
else {
        switch (start) {
            case 'A':  end = 'a';
                     break;
            case 'B':  end = 'b';
                     break;
            case 'C':  end = 'c';
                     break;
            case 'D':  end = 'd';
                     break;
            case 'E':  end = 'e';
                     break;
            case 'F':  end = 'f';
                     break;
            case 'G':  end = 'g';
                     break;
            case 'H':  end = 'h';
                     break;
            case 'I':  end = 'i';
                     break;
            case 'J': end = 'j';
                     break;
            case 'K': end = 'k';
                     break;
            case 'L': end = 'l';
                     break;
            case 'M':  end = 'm';
                     break;
            case 'N':  end = 'n';
                     break;
            case 'O':  end = 'o';
                     break;
            case 'P':  end = 'p';
                     break;
            case 'Q':  end = 'q';
                     break;
            case 'R':  end = 'r';
                     break;
            case 'S':  end = 's';
                     break;
            case 'T':  end = 't';
                     break;
            case 'U':  end = 'u';
                     break;
            case 'V': end = 'v';
                     break;
            case 'W': end = 'w';
                     break;
            case 'X': end = 'x';
                     break;
            case 'Y': end = 'y';
                     break;
            case 'Z': end = 'z';
                     break;
            default: end = '4';
                     break;
}
        }

        return end;
	}

}