Cuffed in Upper W. Side slay

Police have arrested the two teens accused of stabbing a young man on the Upper West Side Thursday and leaving him to bleed to death outside a local pizzeria.

Jashawn Gorham, 18, and Brighton Montgomery, 17, allegedly knifed Tony McClain, 20, about 1:30 p.m. in front of Cheesy Pizza on Broadway and W. 100th St.

McClain tried to get into the pizza joint, but then collapsed. He died at St. Luke’s Hospital. Cops found a knife at the scene. Officers arrested both suspects later near the corner of Amsterdam Ave. and W. 96th St. They are charged with murder, assault and illegal weapons possession.

Investigators believe the killing is gang-related, cop sources said.