#include <stdio.h>
int bitcount(unsigned int a){
	int i =0;
	while(a){
		i++;
		a &= (a-1);
	}
	return i;
}
void lower(char* str){
	char c;
	int i = 0;
	while ((c = str[i]) != '\0' && c!='\n'){
		(c > 'A' && c < 'Z') ? (str[i] = c - 'A' + 'a') : (str[i] = c);
		i++;
	}
}
int main(){
	char test[50] = "HEllo wolrd";
	printf(test);
	lower(test);
	printf(test);
	return 0;
}