Converting a text and number time into a numerical value and converting to minutes

Hi,

I am a very novice excel user and I am trying to solve I think a fairly complex formula.

I am creating a spread sheet from data that is extracted from another program. That program creates a cell for total usage time in the following format: eg. "2d 8h 35m" some will not have the days or hours depending on the amount of time in use "20h 6m" or "45m".

I have approx. 67 columns with the usage times. I would like to get a total at the end.

I have been trying to create a formula that will remove the letter and then convert the "days, hours and min" to straight minutes or one that will add all the cells and move excess min to hours and hours to days.....

I am not even sure where to start. Best I have managed so far is to remove one letter using the substitute formula. I have tried searching the web for help but that seems futile.....

Any suggestions or help would be appreciated.