Hy, I apologize for being maybe a little off topic

the problem is ..

in excel
A1
0:42:58
A2
0:20:30
A3 (=sum a1+a2)
1:03:28

if this is hh:mm:ss its ok! I don't even have to format cells or anything


BUT I have this:

mm:ss,xxx

this xxx is miliseconds and I don't know how to do this:
for example:
A1
01:58,250
A2
02:30,900

A3 (=sum a1+a2)
04:29,150

I don't know how to get this sum in A3 ??

help please

Ivan