Subsequent negotiations led by Jesuit papal legate Antonio Possevino resulted in the 1582 Truce of Jam Zapolski between Russia and the Polish-Lithuanian Commonwealth. This was a humiliation for the Tsar, in part because he requested the truce. Under the agreement Russia would surrender all areas in Livonia it still held and the city of Dorpat to the Polish-Lithuanian Commonwealth, while Polotsk would remain under Commonwealth control. Any captured Swedish territory—specifically Narva—could be retained by the Russians and Velike Luki would be returned from Batory's control to Russia. Possevino made a half-hearted attempt to get John III's wishes taken into consideration, but this was vetoed by the Tsar, probably in collusion with Batory. The armistice, which fell short of a full peace arrangement, was to last ten years and was renewed twice, in 1591 and 1601. Batory failed in his attempts to pressure Sweden into relinquishing its gains in Livonia, particularly Narva. Following a decision by John, the war with Russia ended when the Tsar concluded the Truce of Plussa  with Sweden on 10 August 1583. Russia relinquished most of Ingria but left Narva and Ivangorod under Swedish control. Originally scheduled to last three years, the Russo-Swedish truce was later extended until 1590. During the negotiations, Sweden made vast demands for Russian territory, including Novgorod. Whilst these conditions were probably only for the purposes of negotiation, they may have reflected Swedish aspirations of territory in the region.
Question: How many countries were involved in the 1582 Truce of Jam Zapolski?
Answer: 2