try:
  from icecream import ic
except:
  pass

def minuteToTime(n):
  return f"{str(n//60).zfill(2)}:{str(n%60).zfill(2)}"

def main():
  l,r,m=map(int,input().split())
  print(min(r-l+1,m))
if __name__=="__main__":
  main()