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.
1938
1992
1991
1948
1985
2009
2014
2013
1981
1972
1968
1927
2003
2005
2004
1979
2007
