lastday = ndaymonth(firstmonth,lyfirst)
lastday = ndaymonth(firstmonth,lyfirst) - firstd + 1
lastday = numdays + ndaymonth(currentmonth,lycurrent)
lastday = numdays + lastd - 1
lastday = numdays + lastd
ndays = lastday - firstday + 1
integer lastday
lastday = lastd - 1
lastday = lastd
O lastday,
if ( (lastday .eq. 1) .and. (lastsecs .eq. 0) ) then
lastday = mod(modelenddate(1),100)
if ( firstday .eq. lastday ) then
& lastday ) then