#include <bits/stdc++.h>
using namespace std;

int main() { //legfeljebb t-ig hallgathatjuk, hogy tovabblepjunk
	int n, a, aprev=0; cin>>n;
	map<int, int> cnt;
	queue<int> q;
	for(int i=0; i<n; i++){
		cin>>a;
		cnt[a-aprev]++;
		aprev=a;
	}
	int skip=1;
	q.push(1);
	for(auto x:cnt){
		skip+=x.second;
		q.push(skip);
	}
	cout<<q.size()<<"\n";
	while(!q.empty()){
		cout<<q.front()<<" ";
		q.pop();
	}
}