S=1!+2!+3!+4!+5!+...N!

liuyichen99

#S=1!+2!+3!+4!++...n!
n=int(input())
s=0
for i in range(1,n+1):

    k=1
    for m in range(1,i+1):
         k=k*m

    s=s+k
print(s)




# i! == 1*2*3*4*5*6.....*n
# 6! == 1*2*3*4*5*6
#i!==a1*a2*a3*a4...an


i=int(input()) #n=input()  n=int(n)
k=1
for m in range(1,i+1):
    k=k*m
print(k)



#1+2+3+4...+n?
#a1+a2+a3+a4+an
n=int(input())
s=0
for i in range(1,n+1):
    s=s+i
print(s)