#sum = 0
#for x in range(101):
#	sum = sum + x
#print(sum)
# sum = 0
# n = 99
# while n > 0:
# 	sum = sum + n
# 	n = n - 2
# print(sum)
# L = ['Bart', 'Lisa', 'Adam']
# for x in range(3):
# 	print('Hello,', L[x]+'!')
n = 1
# while n <= 100:
# 	if n > 10:
# 		break
# 	print(n)
# 	n = n + 1
# print('end')
# n = 0
# while n < 10:
# 	n = n + 1
# 	if n % 2 == 0:
# 		# continue
# 		print(n)
# n = 0
# while n < 10:
# 	n = n + 2
# 	print(n-1)
sum = 0 
for i in range(101):
	sum = sum + i
print(sum)
