program long_year(input); var y: integer; function rd_dec31(year: integer): integer; begin { Rata Die of Dec 31, year } rd_dec31 := year * 365 + year div 4 - year div 100 + year div 400 end; function rd_jan1(year: integer): integer; begin rd_jan1 := rd_dec31(year - 1) + 1 end; function weekday(rd: integer): integer; begin weekday := rd mod 7; end; function long_year(year: integer): boolean; var jan1: integer; dec31: integer; begin jan1 := rd_jan1(year); dec31 := rd_dec31(year); long_year := (weekday(jan1) = 4) or (weekday(dec31) = 4) end; begin for y := 1990 to 2050 do if long_year(y) then writeln(y) end.