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| def merge():
global list2
list2.append(list1[0])
for i in range(1, len(list1)):
first = list1[i]
last = list2[-1]
if first[0] <= last[1]:
last[1] = max(last[1], first[1])
else:
list2.append(first)
list1 = []
n = int(input())
#list1 = [[160, 180], [150, 200], [280, 300], [300, 330], [190, 210]] # - >[[150, 200], [160, 180], [190, 210], [280, 300], [300, 330]]
for i in range(n):
#a, b = list1[i][0], list1[i][1]
list1.append(list(map(int, input().split())))
list1.sort(key = lambda x:x[0])
#print(list1)
list2 = []
merge()
ans = 0
for i in range(len(list2)):
ans += list2[i][1] - list2[i][0]
print(ans)
|
