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

int main (int argc, char* argv[])
{
  int n, len;
  FILE *fin;
  char*buff;

  if(argc<3)
  {
    printf("error\n");
    exit(1);
  }

  n=atoi(argv[2]);
  fin=fopen(argv[1], "r");

  fseek(fin,0,SEEK_END);
  len=ftell(fin);
  buff=(char*)malloc(n*sizeof(char));

  rewind(fin);
  fread(buff,sizeof(char),n,fin);
  fwrite(buff,sizeof(char),n,stdout);

  fseek(fin, (len/2)-(n/2), SEEK_SET);
  fread(buff, sizeof(char), n, fin);
  fwrite(buff,sizeof(char),n,stdout);

  fseek(fin, -n, SEEK_END);
  fread(buff, sizeof(char), n, fin);
  fwrite(buff,sizeof(char),n,stdout);

  return 0;

}