https://www.acmicpc.net/problem/1377
n = int(input())
a = [(int(input()), i) for i in range(n)]
a.sort()
ans = 0
for i in range(n):
if a[i][1] - i > ans:
ans = a[i][1] - i
print(ans + 1)
출처: 알고리즘 중급 1/3 강의
https://code.plus/course/43
