Complete the following sentence: Najdorf played eleven times for Argentina in Chess Olympiads from 1950 to 1976. 0=6), as well as at Helsinki 1952 (+11<unk>2=3), Amsterdam 1954, Moscow 1956, Leipzig 1960,
Varna 1962, Havana 1966, Lugano 1968, Siegen 1970, and Haifa 1976. ️<unk>️<unk>️<unk>️<unk>️