basic magnetism on square loop question?

helpmeplz!

A square loop carrying a current I creates its own magnetic field. Describe the forces on each side of the square loop due to its own field. What is the torque it experiences?

My question is this. I know we can use bio savart. But for bio savart, B=uoI/2piR, what R do I use? suppose i have a square loop, the adjacent sides do create B fields that the other experiences, but if they are two consecutive sides, their distance apart is 0? Please someone help me out!!

mfb

You have to integrate over the lines, using the distance between the point where you want to calculate the field and the point where your integral "is".