of the K5 Plan during the dry season offensive of 1984–85, when the base camps of several anti-Vietnamese resistance groups were overrun. Afterwards, the majority of ten Vietnamese divisions were assigned to operations on the frontiers, with the remainder staying in major provinces to protect the local population and to train the Kampuchean armed forces. By 1985, international isolation and economic hardships had forced Vietnam to rely more and more on the Soviet Union for help. During the Chinese invasion in February 1979, the Soviet Union provided US$1.4 billion worth of military aid to Vietnam, a figure that peaked at US$1.7 billion in the period between 1981 and 1985. Then, to help Vietnam implement its third Five Year Plan (1981–1985), the Soviet Union provided a sum of US$5.4 billion to the Vietnamese Government for its expenditures; economic aid ultimately reached US$1.8 billion annually. The Soviet Union also provided 90% of Vietnam's demand for raw materials and 70% of its grain imports. Even though the figures suggest the Soviet Union was a reliable ally, privately Soviet leaders were dissatisfied with Hanoi's handling of the stalemate in Kampuchea and resented the burden of their aid program to Vietnam as their own country was undergoing economic reforms. In 1986, the Soviet Government announced that it would reduce aid to friendly nations; for Vietnam, those reductions meant the loss of 20% of its economic aid and one-third of its military aid. To reengage with the international community, and to deal with the economic challenges brought by the changes in the Soviet Union and Eastern Europe, Vietnamese leaders decided to embark on a series of reforms. At the 6th National Party Congress in December 1986, newly appointed General Secretary of the VCP Nguyen Van Linh introduced a major reform known as Đổi Mới, the Vietnamese term for "renovation", in order to fix Vietnam's economic problems. However, Vietnamese leaders concluded that Vietnam's dire economic situation came as a result of the international isolation which followed its invasion of Kampuchea in 1978, and that for Đổi Mới to be successful it needed radical changes in defence and foreign policy. Subsequently, in June 1987, the Vietnamese Politburo adopted a new defence strategy in Resolution No. 2, calling for the complete withdrawal of Vietnamese soldiers from international duties, a reduction in the size of the army through a discharge of 600,000 soldiers and the establishment of a set ratio