How Do I Do Validation For Height Which Is In Integer But When I Pass String Its Giving Error In Rest Client That Can Not Convert Integer Into String

[Required(ErrorMessage = "Enter Height")]
[Range(0,999, ErrorMessage = "Height is too long")]
[RegularExpression(@"^[0-9]+$", ErrorMessage = "Enter Only Numbers")]

public Nullable<int> Height { get; set; }

{
FighterID: 11,
Height:45,
Weight: 200,
Reach: 33,

}

<pre lang="cs">{
FighterID: 11,
Height:"ghgh"
Weight: 200,
Reach: 33,

}

{
Message: "The request is invalid."
ModelState: {
tblFighters.Height: [2]
0:  "Could not convert string to integer: d. Path 'Height', line 8, position 12."
1:  "Enter Height"
-
}-