The doors of the jam produced by a company do not open. In order for them to be able to sell their jam, they reward the one who can open the jam. All the people try to open the door of the jam.
1995
1916
1991
1999
1980
2006
1964
2003
1972
2001
1976
1961
1990
2009
1979
1957
2002
