for s in range(x) #gives s values from 0 to sqrt(n)

for d in range(0,e,f) #gives d values from 0 to n / sqrt(n)

for si in range(s,e,f) #gives si values from 0 to n / sqrt(n), because the lowest value s has is 0.

for li in range(d,d+f) #gives li values from 0 to sqrt(n)

sqrt(n) * n * / sqrt(n) * n / sqrt(n) * sqrt(n) = n2