#include <bits/stdc++.h>
#define be(v) (v).begin(),(v).end()
#define pb(q) push_back(q)
#define rep(i, n) for(int i=0;i<n;i++)
typedef long long ll;
using namespace std;
const ll mod=1000000007, INF=(1LL<<60);
#define doublecout(a) cout<<fixed<<setprecision(10)<<a<<endl;

int main() {
    cin.tie(0);
    cout.tie(0);
    ios::sync_with_stdio(false);
    ll ans, n;
    cin >> n;
    set<ll> s;
    rep(i, n){
        cin >> ans;
        s.insert(ans);
    }
    ans = 0;
    while(!s.empty()){
        ans++;
        ll now = *s.begin();
        s.erase(now);
        auto itr = s.upper_bound(now + 1);
        while(itr != s.end()){
            now = *itr;
            s.erase(itr);
            itr = s.upper_bound(now + 1);
        }
    }
    cout << ans << endl;
    return 0;
}