Consider quadratic Diophantine equations of the form:

x² – Dy² = 1

For example, when D=13, the minimal solution in x is 649² – 13180² = 1.

It can be assumed that there are no solutions in positive integers when D is square.

By finding minimal solutions in x for D = {2, 3, 5, 6, 7}, we obtain the following:

3² – 22² = 1
2² – 31² = 1
9² – 54² = 1
5² – 62² = 1
8² – 73² = 1

Hence, by considering minimal solutions in x for D 7, the largest x is obtained when D=5.

Find the value of D 1000 in minimal solutions of x for which the largest value of x is obtained.