for /f "tokens=2-4 delims=/ " %%a in ('date /t') do (set mm=%%a&set dd=%%b&set yy=%%c)
 set /a dd=100%dd%%%100,mm=100%mm%%%100
 set /a z=14-mm,z/=12,y=yy+4800-z,m=mm+12*z-3,Jd=153*m+2
 set /a Jd=Jd/5+dd+y*365+y/4-y/100+y/400-32045
 set /a y=yy+4798,Jp=y*365+y/4-y/100+y/400-31738,t=Jp+3,Jp=t-t%%7
 set /a y=yy+4799,Jt=y*365+y/4-y/100+y/400-31738,t=Jt+3,Jt=t-t%%7
 set /a y=yy+4800,Jn=y*365+y/4-y/100+y/400-31738,t=Jn+3,Jn=t-t%%7
 set /a Jr=%Jp%,yn=yy-1,yn+=Jd/Jt,yn+=Jd/Jn
 if %Jd% GEQ %Jn% (set /a Jr=%Jn%) else (if %Jd% GEQ %Jt% set /a Jr=%Jt%)
 set /a diff=Jd-Jr,cw=diff/7+1,wd=diff%%7,wd+=1
 if %cw% LSS 10 set cw=0%cw%