yam, potato, or sweet potato?

I went to have a late lunch at The Pool Cafe (the beach cafe in Maroubra the girls extremely liked when I first brought them there) and saw an interesting side dish on the menu: yam fries. I just got to try it.

The moment I saw those fries, I wondered how much colouring they added to make the yam so orangey in colour. Then when I took a bite, I thought the 'yam' tasted very un-yam-ish. I only realised they were actually deep fried sweet potato sticks, and not yam after gobbling down like 5 - 8 sticks of the orangey fries. Didn't matter to me as they tasted very good with the sweet chilli. A rather refreshing change from the usual fries.