 Complete the following phrase:  The Border Agreement between Poland and the USSR of 16 August 1945 established the borders between the Union of Soviet Socialist Republics USSR and the Republic of Poland. It was signed by the Provisional Government of National Unity Tymczasowy Rząd Jedności Narodowej formed by the Polish communists. According to the treaty, Poland officially accepted the ceding its pre-war Eastern territory to the USSR Kresy which was decided earlier 