Statements of Cash Flows - USD ($)	6 Months Ended
	Jul. 31, 2021	Jul. 31, 2020
Operating activities
Royalties received	$ 25,835,075	$ 4,799,327
Interest received	797	37,338
Expenses paid	(2,221,401)	(1,214,976)
Net cash from operating activities	23,614,471	3,621,689
Investing activities
Maturities of U.S. Government securities	50,942,392	26,899,691
Purchases of U.S. Government securities	(41,035,723)	(23,708,865)
Net cash from investing activities	9,906,669	3,190,826
Financing activity
Distributions to unitholders	(17,712,014)	(16,531,213)
Net change in cash and cash equivalents	15,809,126	(9,718,698)
Cash and cash equivalents, beginning of period	12,500,941	10,177,655
Cash and cash equivalents, end of period	28,310,067	458,957
Reconciliation of net income to net cash from operating activities
Net income	35,329,900	8,287,624
Increase in accrued income receivable	(12,385,176)	(979,139)
Decrease (increase) in contract asset	177,251	(1,059,624)
Increase in prepaid expense	(193,751)	(161,533)
Increase (decrease) in accrued expenses	(210,684)	46,081
Increase (decrease) in contract liability	896,931	(2,511,720)
Net cash from operating activities	23,614,471	3,621,689
Non cash financing activity
Distributions declared and payable	$ 1,180,801	$ 656,001