from __future__ import print_function
import sys
def to_int(x):
  bs = []
  for b in x:
    if bs and bs[-1]:
      bs.append(0 if b == "1" else 1)
    else:
      bs.append(1 if b == "1" else 0)
  return int("".join(map(str, bs)), 2)
n, a, b = sys.stdin.readline().split(); n = int(n)
print(to_int(b) - to_int(a) - 1)