How to animate another div when hover a specific div

Question

So I'm trying to add an animation to the label when input[type="submit"]::hover, I can't figure out which is the correct css selector for that, I wanna know if I can do it using CSS only, if not I'll use jquery:

#thiselement {
  display: block;
  background-color: red;
  border: none;
  color: white;
  height: 3rem;
  width: 14rem;
  border-radius: 24px;
  font-weight: 500;
  font-size: 18px;
  font-family: Poppins, sans-serif;
  align-items: center;
  letter-spacing: 1px;
  align-self: center;
  box-shadow: none;
  transition: all 0.7s ease;
}

#animatethis{
  position: relative;
  width: fit-content;
  color: white;
  left: 10px;
  top: 40px;
  font-size: 2rem;
}

#thiselement:hover > #animatethis{
  animation: lefttoright 1s infinite;
}

@keyframes lefttoright {
  0% {
    left: 10px;
  }
  100% {
    left: 30px;
  }
}

 <label for="submitform" id="animatethis">-</label>
 <input type="submit" name="submitform" id="thiselement" value="Send Message"/>