then have an absorption period in Israel at a kibbutz. Each delegation is adopted by a kibbutz in Israel and has living quarters designated for it. The delegation shares responsibilities in the kibbutz when on military leave. Participants start the program three months before being enlisted in the army at the beginning of August. Marva is short-term basic training for two months. Lev LaChayal is a program based at Yeshivat Lev Hatorah which takes a holistic approach to preparation for service. Being as ready as possible for integrating into Israeli culture, handling the physical challenges of the military, and maintaining religious values require a multi-pronged approach. The beit midrash learning, classes, physical training, and even the recreational activities are designed to allow for maximum readiness. Mission The IDF's mission is to "defend the existence, territorial integrity and sovereignty of the state of Israel. To protect the inhabitants of Israel and to combat all forms of terrorism which threaten the daily life." The Israeli military's primary principles derive from Israel's need to combat numerically superior opponents. One such principle, is the concept that Israel cannot afford to lose a single war. The IDF believes that this is possible if it can rapidly mobilize troops to insure that they engage the enemy in enemy territory. In the 21st Century, various nonconventional threats including terrorist organizations, subterranean infrastructure operated by Hamas, etc. have forced the IDF to modify its official defense doctrine. Doctrine Main doctrine The main doctrine consists of the following principles: Basic points Israel cannot afford to lose a single war Defensive on the strategic level, no territorial ambitions Desire to avoid war by political means and a credible deterrent posture Preventing escalation Determine the outcome of war quickly and decisively Combating terrorism Very low casualty ratio Prepare for defense A small standing army with an early warning capability, regular air force and navy An efficient reserve mobilization and transportation system Move to counterattack Multi-arm coordination Transferring the battle to enemy territory quickly Quick attainment of war objectives Code of conduct In 1992, the IDF drafted a Code of Conduct that combines international law, Israeli law, Jewish heritage and the IDF's own traditional ethical code—the IDF Spirit (, Ru'ah Tzahal). Stated values of the IDF The document defines four core values for all IDF soldiers to follow, as well as ten secondary values (the first being most important, and the others