一

python
n = int(input())
count = 0
a = n//5
for x in range(a+1):
for y in range(a+1):
for z in range(a+1):
if x*5+y*8+z*10 == n:
count+=1
print(count)
二
三

python
n = int(input())
a = list(map(int,input().split()))
c = 0
for i in range(1,n):
for j in range(i):
if a[j]>a[i]:
c+=1
print(c)
四
五

python
n = int(input())
a = list(map(float, input().split()))
c = 0
for i in range(n):
for j in range(i):
if a[i]>a[j]:
c+=1
print(c)
c=0
六
python
n = int(input())
if n == 1:
print(0)
elif n == 2:
print(1)
else:
d_prev_prev = 0 # D(1)
d_prev = 1 # D(2)
for i in range(3, n+1):
d_current = (i-1) * (d_prev + d_prev_prev)
d_prev_prev, d_prev = d_prev, d_current
print(d_prev)
