#B
a11=int(input())
b2=0
for m in range(1,a11+1):
 b2=b2+m
print(b2)

3275302005127952d41f59aa9eddc192c9f2cae0
<mask token>

<mask token>
for m in range(1, a11 + 1):
    b2 = b2 + m
print(b2)

a11 = int(input())
b2 = 0
for m in range(1, a11 + 1):
    b2 = b2 + m
print(b2)

#B
a11=int(input())
b2=0
for m in range(1,a11+1):
 b2=b2+m
print(b2)
