45 czars!

The Ruriks (rulers of Moscow)
Ivan I 1325-1340
Simon 1340-1353
Ivan II 1353-1359
Dimitrij Ivanovich 1359-1389
Vasilij I 1398-1425
Vasilij II 1425-1462
Ivan III 1462-1505
Vasilij III 1505-1533
Ivan IV, the terrible 1533-1584
Feodor I 1584-1598
Boris Godunov 1598-1605
Feodor II 1605
Dimitrij, the false 1605-1606
Vasilij IV Sjujsky 1606-1610

The House of Romanov
Michail III 1613-1645
Alexej Michailovich 1645-1676
Feodor III 1676-1682
Ivan V 1682-1696
Peter I, the great 1682-1725
Catherine I 1725-1727
Peter II 1727-1730
Anna Ivanova 1730-1740
Ivan VI and grand duchess Anna Leopoldovna 1740-1741
Elizabeth 1741-1762

The House of Holstein-Gottorp-Romanov
Peter III 1762
Catherine II, the great 1762-1796
Paul I 1796-1801
Alexander I 1801-1825
Nicholas I 1825-1855
Alexander II 1855-1881
Alexander III 1881-1894
Nicholas II 1894-1917

Just over 30. Compare that to the....czars of Obama! There are 45 of them.... all at once!

Nod to the Blonde.