Sha 256 in java and C# are getting different values

salt="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";


    MessageDigest messageDigest = MessageDigest.getInstance("SHA-256");
    messageDigest.update(salt.getBytes());
    result=new BigInteger(messageDigest.digest());

result=-8679331902525424680818339047284551675590913508739318217139721412571178967790

rawData="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";

using ( SHA256 sha256Hash = SHA256.Create())
	{             
	 var Rawdatabytes = System.Text.Encoding.ASCII.GetBytes(rawData);
	 byte[] bytes = sha256Hash.ComputeHash(Rawdatabytes);              
	 var result = new System.Numerics.BigInteger(bytes);
         
	}

result=8306751456257555796593622157661757526221618682565362023319192974333645213676

for both java and c# are getting different result 
can any one help us to solve the issue

also

for java code we are getting negative value and for c# we are getting positive
please can any one know the solution