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.
1996
1991
1932
1995
1989
2008
2001
1990
1987
1968
1984
1960
2003
1983
1998
2002
1952
