A recursive function f(n)f(n)f(n) is defined by f(n)=f(n−1)−nf(n) = f(n-1) - nf(n)=f(n−1)−n for n≥1n \ge 1n≥1, with f(0)=10f(0) = 10f(0)=10. What is the value of f(1)f(1)f(1)?
101010
999
111111
000