Given the task definition and input, reply with output. This task involves creating questions from a given passage that involve some kind of complex reasoning (including numerical reasoning).
The generated questions must require looking at more than one part of the passage to answer. Try to use a variety of reasoning types in your questions (some of the sample reasoning types are illustrated in the 'positive examples' field) and also have a variety of answer types (spans, numbers, dates). A span is a continuous phrase taken directly from the passage or question. In such questions, the answer spans are recommended to be five words. Questions with answer type "number", are expected to start with "How many". For instance, "How long did an event last?" can be phrased as "How many years did an event last?". To increase diversity, try to create more questions for which the answer will be multiple spans. Please create questions that require AT LEAST 2 arithmetic operations as illustrated in the 'positive examples' field. You are encouraged to try DIFFERENT COMBINATIONS of operations and not just limit to the combinations shown in those examples. The more challenging questions you create, the better it is.

Passage: The Cambodian-Spanish War was an attempt by the Spanish Empire to conquer Cambodia, establish their own king, and Christianize the population. Along with the Spanish, the Japanese, Filipinos, Thai, Portuguese, and Dominicans participated in the invasion of Cambodia. Each country possessed different motives for their invasion of Cambodia. Specifically, the Thai interference and the Spanish expedition was a result of a power struggle between rival factions in Cambodia's government. In addition, both Spanish and Portuguese took part in the invasion of Cambodia because King Philip II ruled both Spain and Portugal. In February 1593, Thai ruler Naresuen attacked Cambodia in order to fight the Burmese. Later on, in May 1593, 100,000 Thai soldiers invaded Cambodia. As a result of the Thai's invasion, Lovek was conquered in July 1594. In 1593, the Spanish expedition led by Gregorio Vargas Machuca and Blas Ruiz de Hernan Gonzales entered Cambodia through the city of Manila.Although the Spanish invasion of Cambodia failed, Ruiz and Veloso succeeded in establishing king Barom Reachea II in May 1597. Private individuals of Muslim Malays, Chams, Cambodians retaliated to Spain and Portugal's invasion by slaughtering the Spanish and Portuguese, including Diogo Veloso. Only a few Filipinos and one Spaniard survived the massacre. Because of the massacre, Spain's planned Christianization of Cambodia failed. After the attack, Cambodia came under the dominance of the Thai in July 1599.
How many countries participated in the invasion of Cambodia?