How many German soldiers fought in D'Day as well as the Battle of Berlin?

If you are asking solely about German soldiers who fought the Allies in Normandy on June 6th 1944 then the answer is quite possibly 'none'.

Firstly, the units defending the beaches on D-Day were all but destroyed during that day and the few days/weeks after. The 352nd Infantry Division, defenders at Omaha beach, was disbanded at the end of July and reformed (with new troops) as the 352nd Volksgrenadier Division in September 1944. Specifically for Utah Beach the surviving Germans troops were effectively cutoff by the US Airborne landings and the Carentan canal. They were forced back north towards Cherbourg and were killed or surrendered at some point during the Allied drive up the Cotentin peninsula.

Secondly the Battle of Berlin was fought between the Germans and the Soviet Red Army, the western Allies had no part in it. Red Army spearheads had already pushed well past Berlin by the time the battle began and the defenders were all remnants of units that had been fighting on the Eastern front or hastily formed Volksturm units. While some units, primarily armored, were moved between the Eastern and Western fronts at various times during the war, by this stage the German capacity for strategic movement was virtually non-existent and the units defending in the West were stuck there.

In order to know the answer to this question you would need to dig through the service records of thousands of German soldiers to follow their path. Off the top of my head the only person that I know to have served in Normandy and in Berlin was Wilhelm Mohnke, an SS officer who commanded a panzer-grenadier regiment in the 12th SS during the Normandy campaign and was later commander of the forces around the Reich Chancellery during the Battle for Berlin. However his unit did not see action in Normandy until the day after the landings.