So the myosin heads contain ATP molecules or an ATP molecule. So one ATP per hour myosin head. Now before they can actually bind to the mycin binding side that was just exposed as a result of the binding, the calcium, the ATP must be hydrolyzed into ADP and a phosphate group. So basically this ATP that is found on the myosin ahead of our thick filament, so this is a thick filament, this is our myosin head, which is basically our myosin heads. On this thick filament shown here, it is hydrolyzed and the ADP and the P that are produced remain on that myosin head. So this is step three.