Prussia emerged from the Silesian Wars as a new great power whose continental importance could no longer be disputed, and the leading power of Protestant Germany.:215-219 The kingdom had gained control of extensive new lands in Silesia, a densely industrialized region  with a large population and substantial tax yields.:192 Frederick the Great's personal reputation was enormously enhanced by his successes in the wars, as his debts to fortune  and to British financial support were soon forgotten, while the memories of his energetic leadership and tactical genius were strenuously kept alive.:90 His small kingdom had defeated the Habsburg Monarchy and defended its prize against Austria, Russia, Sweden, and  France, an accomplishment that appeared miraculous to contemporary observers.:200 After 1763, armies around the world sent their officers to Prussia to learn the secrets of the realm's outsize military power, making Prussia one of the most imitated states in Europe.:90
Question: How many countries did Frederick the Great successfully defend against?
Answer: 4