/* Compare to dbl.c. */

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

int chararray_append(char **a,int *aspace,int *alen,char c)
{
  if (*alen == *aspace) {
    int yspace = *aspace * 2 + 1;
    char *y = (char *) realloc(*a,yspace);
    if (!y) return 0;
    *a = y;
    *aspace = yspace;
  }
  (*a)[*alen] = c;
  ++*alen;
  return 1;
}

int main(void)
{
  char *x = 0;
  int xspace = 0;
  int xlen = 0;
  char c;
  int i;

  while (scanf("%c",&c) == 1) {
    if (!chararray_append(&x,&xspace,&xlen,c)) {
      printf("out of memory\n");
      exit(1);
    }
    if (c == '\n') {
      for (i = 0;i < xlen;++i) putchar(x[i]);
      for (i = 0;i < xlen;++i) putchar(x[i]);
      xlen = 0;
    }
  }

  return 0;
}