I need help on this OPM question

PA 9-3 A company making tires for bikes is concerned... A company making tires for bikes is concerned about the exact width of their cyclocross tires. The company has a lower specification limit of 22.6 mm and an upper specification limit of 23 mm. The standard deviation is 0.14 mm and the mean is 22.8 mm. (Round your answer to 4 decimal places.) What is the process capability index for the process? 1.2110