#include<iostream>
#include<cstdio>
#include<algorithm>
using namespace std;
int n, MAX = 1, m = 1, s = 0, N = 0, a[123456789];
int main() {
	cin >> n;
	for (int i = 0; i < n; i++) {
		cin >> a[i];
		N == 0 ? N = 1, s = a[i] : (a[i] == s++ ? m++ : (m > MAX ? MAX = m : 0), m = 1, N = 0);
	}
}

求助！！