import java.lang.IllegalArgumentException;
import java.util.List;
import java.util.ArrayList;

class Series {

  public String series;

  public Series(String series) {
    this.series = series;
  }

  public List<String> slices(int n) {
    if (n < 1) {
      throw new IllegalArgumentException("Slice size is too small.");
    } else if (n > series.length()) {
      throw new IllegalArgumentException("Slice size is too big.");
    }

    List<String> result = new ArrayList<>();
    int index = 0;
    while (index + n - 1 != series.length()) {
      result.add(series.substring(index, index + n));
      index++;
    }

    return result;
  }

}