import fit.Fixture;

public class Spreadsheet extends Fixture {
    String lastAddress = "?";

    public void a1(String contents) {
        lastAddress = "a1";
    }

    public String a1() {
        return "?";
    }

    public void b1(String contents) {
        lastAddress = "b1";
    }

    public String b1() {
        return "?";
    }
 
    public String formula() {
        // formula for "lastAddress"
        return "=?";
    }
}