Roxanne has 1/2 as many beads as Sherie. The number of beads sherie has is 4/5 that of Marcos. Marcos has 165 beads. How many more beads does Marcos have than Roxanne?

Roxanne has 1/2 as many beads as Sherie. The number of beads sherie has is 4/5 that of Marcos. Marcos has 165 beads. How many more beads does Marcos have than Roxanne?