A company tests all new brands of golf balls to ensure they meet certain specifications. One test conducted is intended to test the average distance traveled when the ball is hit by a machine. Suppose the company wishes to estimate the mean distance for a new brand to within 1.4 yards with 90% confidence. Assume past tests have indicated that the standard deviation of the distances the machine hits the golf balls is approx. 14 yards. How many golf balls should be hit by the machine to achieve the desired accuracy in estimating the mean? Round up to the nearest golf ball.