Passage: On 28 January 2009, Japan announced its intention of sending a naval task force to join international efforts to stop piracy off the coast of Somalia. The deployment would be highly unusual, as Japan's non-aggressive constitution means Japanese military forces can only be used for defensive purposes. The issue has been controversial in Japan, although the ruling party maintains this should be seen as fighting crime on the high seas, rather than a "military" operation. The process of the Prime Minister of Japan, Taro Aso, giving his approval is expected to take approximately one month. However, the Japanese Maritime Self-Defense Force (JMSDF) and the Japanese government face legal problems on how to handle attacks by pirates against ships that either have Japanese personnel, cargo or are under foreign control instead of being under Japanese control as current Article 9 regulations would hamper their actions when deployed to Somalia. It was reported on 4 February 2009, that the JMSDF was sending a fact-finding mission led by Gen Nakatani to the region prior to the deployment of the Murasame-class destroyer Samidare and the Takanami-class destroyer Sazanami to the coast of Somalia with a 13-man team composed of Japanese Ministry of Defense personnel, with members coming from the Ministry of Foreign Affairs and the JMSDF to visit Yemen, Djibouti, Oman, and Bahrain from 8 to 20 February. Both JMSDF vessels are units of the 8th Escort Division of the 4th Escort Flotilla based in Kure, Hiroshima Prefecture. The JMSDF's special forces unit, the Special Boarding Unit is also scheduled to potentially deploy to Somalia. The SBU has been deployed alongside the two destroyers to Somalia on 14 March 2009. According to JMSDF officials, the deployment would "regain the trust of the shipping industry, which was lost during the war." The JMSDF task force would be deployed off the coast of Somalia for 4 months. In its first mission, the Sazanami was able to ward off pirates attempting to hijack a Singaporean cargo ship. In addition, JMSDF P-3Cs are to be deployed in June from Djibouti to conduct surveillance on the Somali coast. The House of Representatives of Japan has passed an anti-piracy bill, calling for the JMSDF to protect non-Japanese ships and nationals, though there are some concerns that the pro-opposition House of Councillors may reject it. The Diet of Japan has passed an anti-piracy law that called for JMSDF forces to protect all foreign ships traveling off the coast of Somalia aside from protecting Japanese-owned/manned ships despite a veto from the House of Councillors, which the House of Representatives has overturned. In 2009, the Murasame-class destroyer Harusame and the Asagiri-class destroyer Amagiri left port from Yokusuka to replace the two destroyers that had been dispatched earlier in March 2009. Under current arrangements, Japan Coast Guard officers would be responsible for arresting pirates since SDF forces are not allowed to have powers of arrest.
 Link Information: The process of the Prime Minister of Japan, Taro Aso, Question: How long had the prime minister served in that position at the time of the announcement of the anti-piracy measures?
Output: Answer: 4