#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

int main()
{
	char *pc=(char*)malloc(sizeof(char));
	unsigned int i=0,j;
	char app;
	while(read(0,pc+i++,1))
		pc=(char*)realloc(pc,(i+1)*sizeof(char));
	i--;//Ora i rappresenta l'indice del terminatore di stringa
	*(pc+i)='\0';
	for(j=0;j<i/2;j++)
	{
		app=*(pc+j);
		*(pc+j)=*(pc+i-1-j);
		*(pc+i-1-j)=app;
	}
	printf("%s",pc);
	return 0;
}