I think they consider 1700, 1800, 1900 as being leap years whereas in the problem statement these years are not considered so.

http://www.timeanddate.com/calendar/index.html?year=1700&country=20

1700, 1800, 1900 are not leap years;
year Y is leap
if
Y mod 4 = 0
if
Y mod 400 = 0
but
if Y mod 100 = 0 and Y mod 400 <> 0 then the year is not leap

Your link lies.
This years are not leap.
http://en.wikipedia.org/wiki/Leap_year

yeah thx i know those years are not leap ones.
i was just a little confused with the january 1st 1600.
my solution got AC

thx anyway

In the Julian calendar every year that is divisible by 4 is leap. in Gregorian if year is century must be divisible by 400 to be leap. it is so because in every 400 years by julian 3 exess days(to be more certain 1 in 128 years). we began to use gregorian calendar after 1900 year so you see every year before 1918 if year is divisible by 4 then it is leap.

Very interesting fact.