A=io.read("n")
B=io.read("n")
S=io.read()
local res="Yes"
for i=1,#S do
  if i==A+1 then
    if string.sub(S,i,i)~="-" then
      res="No"
    end
  elseif string.sub(S,i,i)<"0" or string.sub(S,i,i)>"9" then
      res="No"
  end
end
print(res)

