function main()
  
  (A,B) = map(x -> parse(Int,x), split(readline()))
  
  S = split(chomp(readline()),"")
  
  check = true
  for i in 1:A+B+1
    
    if i == A+1 && S[i] != "-"
      check = false
    elseif i != A+1 && typeof(S[i]) == Int64 && (parse(Int,S[i]) < 0 || 9 < parse(Int,S[i]))
      check = false
    end
    
  end
  
  if check == true
    println("Yes")
  else
    println("No")
  end
  
end

main()