How to change input value

<!DOCTYPE html>
<html>
<head>
<title></title>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width">
<style>
   body {  overflow:hidden;    }
   #input {   font-size:30px;       }
   #span {   padding:10px 30px;border:1px solid;cursor:pointer;   }
</style>
</head>
<body>
<input type='text' id='input' value='bring me some potato' size='50'/><p>
<span id='span'>onclick change input font-size</span>

<script>
span.onclick=()=>{
input.style.fontSize='80px';
input.style.fontFamily='Segoe Script';
}
</script>
</body>
</html>