Subway, the world's largest restaurant chain, grew from one Connecticut storefront to nearly 45,000 locations in more than 100 countries. But the company shrank for the first time in 2016. Now, it hopes a new look will help jumpstart the 50-year-old brand. In a story you'll see only on "CBS This Morning," Norah O'Donnell spoke with Subway CEO and lifelong employee Suzanne Greco. She opened up in her first TV interview about taking over the company started by her big brother, and the struggles of staying competitive in the fast food industry.