perl -MTime::Local -e "print timelocal@ARGV[5,4,3,2],--$ARGV[1],@ARGV" 2008 4 1 6 5 4

($Y,$M,$D,$h,$m,$s)=@ARGV;--$D;$D+=365+!($_%4)for 1970..$Y-1;$D+=$_-2?31-$_*.86
%2:28+!($Y%4)for 1..$M-1;print$s+60*(60*(24*$D+$h-9)+$m),$/