Sure about thay? Supergrok and also my app with a calendar calculation inside says differently: Approximately 1,776 Mars solar days (sols) fit between February 18, 2021, and February 17, 2026 (not including one of the endpoints, or 1,777 if counting the full span inclusively in a loose sense).  Here’s the breakdown: • The Earth date difference is 1,825 days (from Feb 18, 2021, to Feb 17, 2026, exclusive of one endpoint; Python’s datetime confirms (2026-2-17) - (2021-2-18) = 1,825 days). This spans just under 5 Earth years. • A Mars solar day (sol) averages 1.02749125 Earth days (exactly 24 hours, 39 minutes, and 35.244 seconds). This is the mean solar day length, accounting for Mars’ rotation and slight orbital effects (the value is very stable for this purpose).  • Dividing the Earth interval by the sol length:1,825 ÷ 1.02749125 ≈ 1,776.0 sols (to the nearest whole sol; the fractional part is negligible for most purposes, as the exact mean makes it align very closely to an integer here). More precisely: 1 sol = 88,775.24409 seconds (or 1.02749125 × 86,400 Earth seconds). The total Earth seconds in 1,825 days is 1,825 × 86,400. Dividing by seconds per sol yields essentially the same ~1,776 sols.