// your code goes here
var regex = /\[fontSize=(\d+)\]/ ;
var str = "Lorem ipsum dolor sit amet, [b]consectetur adipisici elit[/b], sed eiusmod tempor incidunt ut labore et [fontSize=12]dolore [/fontSize=12] magna aliqua" ;
var match = regex.exec ( str) ;
var fontSize = match[ 1 ] ;
print( fontSize) ;
Ly8geW91ciBjb2RlIGdvZXMgaGVyZQp2YXIgcmVnZXggPSAvXFtmb250U2l6ZT0oXGQrKVxdLzsKdmFyIHN0ciA9ICJMb3JlbSBpcHN1bSBkb2xvciBzaXQgYW1ldCwgW2JdY29uc2VjdGV0dXIgYWRpcGlzaWNpIGVsaXRbL2JdLCBzZWQgZWl1c21vZCB0ZW1wb3IgaW5jaWR1bnQgdXQgbGFib3JlIGV0IFtmb250U2l6ZT0xMl1kb2xvcmUgWy9mb250U2l6ZT0xMl0gbWFnbmEgYWxpcXVhIjsKdmFyIG1hdGNoID0gcmVnZXguZXhlYyhzdHIpOwp2YXIgZm9udFNpemUgPSBtYXRjaFsxXTsKcHJpbnQoZm9udFNpemUpOw==