C :

#include<stdio.h>
int main(){
char c;
c=getchar();
if(c>='A' && c<='Z')
  printf("%c\n",c+32);
else
  printf("%c\n",c);
return 0;
}

C++ :

#include <stdio.h>
int main() {
	char c;
	scanf("%c", &c);
	if ('A' <= c && c <= 'Z')
		c += 'a' - 'A';
	printf("%c\n", c);
	return 0;
}

Pascal :

var
  a:char;
  s:longint;
begin
  readln(a);
  s:=ord(a)+32;
  writeln(chr(s));
end.

Java :

import java.util.*;
public class Main {
	public static void main(String args[]) {
		Scanner cin=new Scanner(System.in);
		String s=cin.next();
		System.out.println(s.toLowerCase());
	}
}

Python :

print raw_input().lower()