#include <bits/stdc++.h>
#define rep(i,n) for(int i=0;i<(int)(n);i++)
using namespace std;
using ll = long long ;
using P = pair<int,int> ;
using pll = pair<long long,long long>;
constexpr ll INF = 1e9;
constexpr long long LINF = 1e17;
constexpr int MOD = 1000000007;
constexpr double PI = 3.14159265358979323846;

int main(){
    int n;
    cin >> n;
    vector<ll> a(n);
    rep(i,n) cin >> a[i];
    set<ll> st;
    rep(i,n) st.insert(a[i]);
    int cnt = 0;
    while(!st.empty()){
        auto it = st.begin();
        while(it != st.end()){
            auto itr = st.upper_bound((*it)+1);
            if(itr == st.end()){
                st.erase(it);
                break;
            }
            else{
                st.erase(it);
                it = itr;
            }
        }
        ++cnt;
    }
    cout << cnt << endl;

    return 0;
}