//

// Created by houruizhe on 2020/10/31.

//

#include <vector>

#include <algorithm>

#include <iostream>

using namespace std;

typedef long long LL;

class Solution {

public:

/**

* @param N: a positive integer N

* @return: return a maximum integer less than N, each digit of which must be monotonically increasing.

*/

long long getIncreasingNumber(long long N) {

// write your code here

if (N >= 123456789) return 123456789L;

LL res = 0;

int pre = 10, digit = 1;

while (N != 0) {

LL mod = N % 10;

LL small = mod < pre - 1 ? mod : pre - 1;

res += digit * small;

digit *= 10;

pre = small;

N /= 10;

}

return res;

}

};

int main() {

auto *sol = new Solution();

auto res = sol->getIncreasingNumber(998);

cout << res << endl;

return 0;

}