What follows is an opinion from a United States Court of Appeals.
Intervenors who participated as parties at the courts of appeals should be counted as either appellants or respondents when it can be determined whose position they supported. For example, if there were two plaintiffs who lost in district court, appealed, and were joined by four intervenors who also asked the court of appeals to reverse the district court, the number of appellants should be coded as six.
In some cases there is some confusion over who should be listed as the appellant and who as the respondent. This confusion is primarily the result of the presence of multiple docket numbers consolidated into a single appeal that is disposed of by a single opinion. Most frequently, this occurs when there are cross appeals and/or when one litigant sued (or was sued by) multiple litigants that were originally filed in district court as separate actions. The coding rule followed in such cases should be to go strictly by the designation provided in the title of the case. The first person listed in the title as the appellant should be coded as the appellant even if they subsequently appeared in a second docket number as the respondent and regardless of who was characterized as the appellant in the opinion.
To clarify the coding conventions, consider the following hypothetical case in which the US Justice Department sues a labor union to strike down a racially discriminatory seniority system and the corporation (siding with the position of its union) simultaneously sues the government to get an injunction to block enforcement of the relevant civil rights law. From a district court decision that consolidated the two suits and declared the seniority system illegal but refused to impose financial penalties on the union, the corporation appeals and the government and union file cross appeals from the decision in the suit brought by the government. Assume the case was listed in the Federal Reporter as follows:
United States of America,
Plaintiff, Appellant
v
International Brotherhood of Widget Workers,AFL-CIO
Defendant, Appellee.
International Brotherhood of Widget Workers,AFL-CIO
Defendants, Cross-appellants
v
United States of America.
Widgets, Inc. & Susan Kuersten Sheehan, President & Chairman
of the Board
Plaintiff, Appellants,
v
United States of America,
Defendant, Appellee.
This case should be coded as follows:Appellant = United States, Respondents = International Brotherhood of Widget Workers Widgets, Inc., Total number of appellants = 1, Number of appellants that fall into the category "the federal government, its agencies, and officials" = 1, Total number of respondents = 3, Number of respondents that fall into the category "private business and its executives" = 2, Number of respondents that fall into the category "groups and associations" = 1.
Note that if an individual is listed by name, but their appearance in the case is as a government official, then they should be counted as a government rather than as a private person. For example, in the case "Billy Jones & Alfredo Ruiz v Joe Smith" where Smith is a state prisoner who brought a civil rights suit against two of the wardens in the prison (Jones & Ruiz), the following values should be coded: number of appellants that fall into the category "natural persons" =0 and number that fall into the category "state governments, their agencies, and officials" =2. A similar logic should be applied to businesses and associations. Officers of a company or association whose role in the case is as a representative of their company or association should be coded as being a business or association rather than as a natural person. However, employees of a business or a government who are suing their employer should be coded as natural persons. Likewise, employees who are charged with criminal conduct for action that was contrary to the company policies should be considered natural persons.
If the title of a case listed a corporation by name and then listed the names of two individuals that the opinion indicated were top officers of the same corporation as the appellants, then the number of appellants should be coded as three and all three were coded as a business (with the identical detailed code). Similar logic should be applied when government officials or officers of an association were listed by name.
Your specific task is to determine the total number of appellants in the case that fall into the category "natural persons". If the total number cannot be determined (e.g., if the appellant is listed as "Smith, et. al." and the opinion does not specify who is included in the "et.al."), then answer 99.

Opinion:
Vincent B. WELCH, Appellant, v. Robert W. SHERWIN et al., Appellees.
No. 16312.
United States Court of Appeals District of Columbia Circuit.
Argued Oct. 10, 1961.
Decided Feb. 8, 1962.
Mr. John A. Kendrick, Washington, D. C. , with whom Mr. E. Tillman Stirling, Washington, D. C., was on the brief, for .appellant.
Mr. Mark P. Friedlander, Washington, D. C., with whom Messrs. Mark P. Fried-lander, Jr., and Blaine P. Friedlander, Washington, D. C., were on the brief, for appellees.
Before Edgerton, Bazelon and Fahy, Circuit Judges.
BAZELON, Circuit Judge.
This is a suit for an attorney’s fee of $12,718.41 based upon a written contract under which defendants, members of the Creditors’ Committee of an insolvent corporation, “assume[d] responsibility for payment of plaintiff’s fees * * * regardless of any arrangement the Creditors’ Committee may have or may obtain for reimbursement.” After trial, without .jury, the District Court found that a discussion between the parties which preceded execution of the contract led the defendants to understand “that in signing the agreement they would be technically liable for attorney’s fees and costs, but that * * * if the [debtor] corporation assumed [such] liability * * * the individual creditors would not be held responsible.” Finding that the corporation had assumed but had not paid the debt, the court denied recovery under the contract. Plaintiff appeals.
We think the District Court erred. There is no allegation or finding of fraud, mistake or overreaching. And the contemporaneous oral “understanding” upon which the trial court relied contradicts the plain language of the contract.
“[W]here parties enter into a written contract, their rights must be controlled thereby, and, in the absence of fraud or mistake, all evidence of any contemporaneous oral agreement on the same subject matter, contradicting, varying, modifying, or adding to the terms of the written agreement is inadmissible. Shankland v. Mayor, etc., 5 Pet. 390, 30 U.S. 390, 8 L.Ed. 166, affirming Shankland v. Corporation of Washington, Fed.Cas.No. 12,703, 3 Cranch C.C. 328; Selden v. Myers, 20 How. 506, 61 U.S. 506, 15 L.Ed. 976; Willard v. Tayloe, 8 Wall. 557, 75 U. S. 557, 19 L.Ed. 501. The written contract merges all previous negotiations and is presumed, in law, to express the final understanding of the parties. Brawley v. United States, 96 U.S. 168, 24 L.Ed. 622; Van Ness v. Mayor, etc., of City of Washington, 4 Pet. 232, 29 U.S. 232, 7 L.Ed. 842, affirming Van Ness v. United States, Fed.Cas.No. 16,868, 2 Cranch C.C. 376, 2 D.C. 376; Kinney v. Mc-Nabb, 44 App.D.C. 340” [Boomhower, Inc. v. Louis L. Lavine, 151 F.Supp. 563, 567 (D.D.C.1957).]
It follows that the instant contract must be enforced as written.
The question remaining is whether the defendants are jointly liable for the entire fee or severally liable for only a “pro rata” share. We are constrained to hold that they are jointly liable for the entire fee.
The contract provides that “the members of the Committee as such assume[d] responsibility for payment,” and contains no words of severance. The general rule is “that the obligation created by the promise of several persons is joint unless the contrary is made evident.” 2 Willis-ton, Contracts § 323 (1936). Cf. Restatement, Contracts § 112 (1932). Moreover, the contract identifies the promisors as “the members of the Committee” and discloses an undivided promise to pay the entire fee. This negates the view that each member made a separate promise to pay a pro rata share. See 4 Corbin, Contracts § 925 (1951). Compare Huff v. Doerr, 206 Mo.App. 563, 228 S.W. 849 (1921), with O’Connor v. Hooper, 102 Cal. 528, 36 P. 939 (1894). Cf. Olson v. Forster, 42 Cal.App.2d 493, 109 P.2d 388 (1941). Compare Adriatic Fire Ins. Co. v. Treadwell, 108 U.S. 361, 2 S.Ct. 772, 27 L.Ed. 754 (1883). Finally, the common object of the members of the Creditors’ Committee — to secure appellant’s legal services — suggests that their liability is joint. 4 Corbin, Contracts § 926 (1951).
Whether the members of the Creditors’ Committee are entitled to contribution inter se or from other creditors, or both, *s no^ before us.
Reversed and remanded.
. The court below awarded plaintiff $505.-83, presumably as third party beneficiary of another contract in which defendants as creditors promised to pay a portion of the Committee’s expenses based upon their share of the corporation’s debts.
. Fraud is an affirmative defense which must be pleaded. Fed.R.Civ.P. rule 8(c), 28 U.S.C.A.
Counsel admitted that defendants are experienced businessmen, well aware of the importance of written agreements. Compare Hill v. Marston, 65 App.D.C. 250, 82 F.2d 856 (1936).
. The terms joint, several, and joint and several have occasionally been confused. Co-promisors are liable (1) jointly if all of them have promised the entire performance; or (2) severally if they have promised separate performances. At common law joint promisors had to be joined in a single suit, but any one of them could be compelled to satisfy the entire judgment. 4 Corbin, Contracts §§ 920, 929 (1951). To obviate the necessity for joining all the promisors, and to avoid problems of survivorship, release of co-obligors, and the like, the promisee obtained the promisors’ agreement to be liable jointly and severally; i. e., collectively and individually liable for the whole performance.
In this jurisdiction, statutes authorize separate suits against joint promisors even if they have not agreed to be liable jointly and severally. D.C.Code §§ 13-401, 16-901 (1961). Those statutes do not determine, of course, whether each co-promisor has agreed to be liable for the entire performance or only for a part thereof. That determination is governed by the terms of the contract.

Question: What is the total number of appellants in the case that fall into the category "natural persons"? Answer with a number.

Choices:

Answer: 1