a,b = map(int,input().split())
s = list(input())
if s[a] == "-" and len(s) == a+b+1:
  s.remove(s[a])
  for i in range(a+b):
    if i.is_integer() == False:
      print("No")
      break
  else:
    print("Yes")
else:
  print("No")