memset(buffer1, 0, (N+1) * sizeof(char));
memset(buffer2, 0, (N+1) * sizeof(char));
i=0;
  }


    if(i < N)               //prvotní nacteni do bufferu ze vstupu
      {
      buffer1[i%N] = c;
      i++;
      }
      else if(i < 2 * N)
        {
        buffer2[i%N] = c;
        i++;
        }