#include <iostream>
#include <set>

int main() {
	size_t n;
	std::cin >> n;
	std::set<int> st;
	for (size_t i = 0; i < n; i++) {
		int a;
		std::cin >> a;
		st.insert(a);
	}
	
	int ans = 0;
	while (not st.empty()) {
		int cur = *st.begin();
		st.erase(st.begin());
		ans++;
		
		while (not st.empty()) {
			auto next = st.upper_bound(cur + 1);
			if (next == st.end()) break;
			cur = *next;
			st.erase(next);
		}
	}
	
	std::cout << ans << '\n';
	return 0;
}