 Complete the following phrase:  Melodi Grand Prix has failed to be staged on three previous occasions. In 1970, Norway was absent from the contest because of a Nordic boycott of the voting system, which had led to a four-way tie for first place at the 1969 contest. In 1991, the event was canceled after the NRK understood that the quality of the competing songs was weak and opted for an internal selection to choose the song which go to Rome. The final instance of no Melodi Grand Prix was in 2002, when Norway was relegated from competing in the 2002 Contest after coming last 