Buggy python submission (verdict: Runtime Error):
import sys
# input関係の定義
sys.setrecursionlimit(200000)
input = sys.stdin.readline
def ii(): return int(input())
def mi(): return map(int, input().rstrip().split())
def lmi(): return list(map(int, input().rstrip().split()))
def fi(): return float(input())
def mfi(): return map(float, input().rstrip().split())
def lmfi(): return list(map(float, input().rstrip().split()))
def li(): return list(input().rstrip())
def debug(*args, sep=" ", end="\n"): print("debug:", *args, file=sys.stderr, sep=sep, end=end) if not __debug__ else None
def exit(*arg): print(*arg); sys.exit()
# template

# BEGIN CUT HERE
class RollingHash():
    """ロリハ。容易に衝突するので注意。"""
    BASE1 = 1007
    BASE2 = 2009
    MOD1 = 1000000007
    MOD2 = 1000000009

    def __init__(self, s, opt=2):
        self.n = len(s)
        self.opt = opt
        self.hash1 = [0] * (self.n + 1)
        self.power1 = [1] * (self.n + 1)
        if opt == 2:  # rollinghash by 2 mod
            self.hash2 = [0] * (self.n + 1)
            self.power2 = [1] * (self.n + 1)

        for i, e in enumerate(s):
            self.hash1[i + 1] = (self.hash1[i] * self.__class__.BASE1 + ord(e)) % self.__class__.MOD1
            self.power1[i + 1] = (self.power1[i] * self.__class__.BASE1) % self.__class__.MOD1
        if opt == 2:  # rollinghash by 2 mod
            for i, e in enumerate(s):
                self.hash2[i + 1] = (self.hash2[i] * self.__class__.BASE2 + ord(e)) % self.__class__.MOD2
                self.power2[i + 1] = (self.power2[i] * self.__class__.BASE2) % self.__class__.MOD2

    def get(self, l: int, r: int):
        res1 = self.hash1[r] - self.hash1[l] * self.power1[r - l] % self.__class__.MOD1
        if(res1 < 0):
            res1 += self.__class__.MOD1
        if self.opt == 2:
            res2 = self.hash2[r] - self.hash2[l] * self.power2[r - l] % self.__class__.MOD2
            if(res2 < 0):
                res2 += self.__class__.MOD2
        return (res1, res2) if self.opt == 2 else res1
# END CUT HERE

def ABC131E():
    N = ii()
    S = li()
    rh = RollingHash(S, opt=1)
    def check(n: int):
        d = dict()
        for i in range(N - n + 1):
            p = rh.get(i, i + n)
            if p in d:
                if(i - d[p] >= n):
                    return True
            else:
                d[p] = i
        return False
    ok, ng = 0, N // 2 + 1
    while ng - ok > 1:
        mid = (ok + ng) // 2
        if check(mid):
            ok = mid
        else:
            ng = mid
    print(ok)



if __name__ == '__main__':
    ABC131E()


Fixed submission:
# -*- coding: utf-8 -*-
import sys
from operator import itemgetter
from fractions import gcd
from math import ceil, floor, sqrt
from copy import deepcopy
from collections import Counter, deque
import heapq
from functools import reduce
sys.setrecursionlimit(200000)
# local only
# if not __debug__:
#     fin = open('in_1.txt', 'r')
#     sys.stdin = fin
# local only
# input = sys.stdin.readline
# def ii(): return int(input())
# def mi(): return map(int, input().rstrip().split())
# def lmi(): return list(map(int, input().rstrip().split()))
# def fi(): return float(input())
# def mfi(): return map(float, input().rstrip().split())
# def lmfi(): return list(map(float, input().rstrip().split()))
# def li(): return list(input().rstrip())
# def debug(*args, sep=" ", end="\n"): print("debug:", *args, file=sys.stderr, sep=sep, end=end) if not __debug__ else None
# def exit(*arg): print(*arg); sys.exit()
# template


def main():
    a = ["Sunny", "Cloudy", "Rainy"]
    S = input()
    if S == a[0]:
        print(a[1])
    elif S == a[1]:
        print(a[2])
    else:
        print(a[0])
    return


if __name__ == '__main__':
    if not __debug__:
        import doctest
        doctest.testmod()
    main()