date1 : 290678400
date2 : 1163577600

date1 : 328950000
date2 : 1163577600

for 29th Feb
date1 : 320659200

For 4/27/1980
date1 : 325670400
date2 : 1163577600

For 4/28/1980
date1 : 325753200  / 325756800
date2 : 1163577600

For 4/29/1980
date1 : 325839600
date2 : 1163577600

1163491200

325753200 - 325670400 = 82800

82800/3600 = 23