When you can't figure out the tune in your head

We were on our way to lunch yesterday when my colleague yawned and she yawned the first 4 notes of a classical piece of music. 

Try as I might, using all the apps and websites I could find to try identify it, I couldn't figure out what music it was. 

It was really irritating!

I still couldn't get it out of my mind this morning and I had to ask a friend. I sent him the first 4 notes and he asked me to check out the concertos by Tchaikovsky. 

The amusing thing was that the first video I checked out in YouTube is the right one. 

pearlie