#include <iostream>
#include <algorithm>
using namespace std;
const int maxn = 2502;

int n;
int a[maxn];

int dp[maxn];

int rec(int at) {

    if(dp[at] != -1) {
        return dp[at];
    }
    int res = 1;


    for(int i = at + 1; i < n; i++) {
        if(a[at] < a[i]) {
            res = max(res, rec(i) + 1);
        }
    }

    dp[at] = res;
    return res;
}
int main() {

    memset(dp, -1, sizeof dp);
    cin >> n;

    for(int i = 0; i < n; i++) {
        cin >> a[i];
    }

    int res = 0;
    for(int i = 0; i < n; i++) {
        res = max(res, rec(i));
    }

    cout << res << endl;
    return 0;
}
// rec(0) = rec(6) + 1 = 2
// rec(0) = rec(7) + 1 = 2
// rec(6) = 1
// rec(7) = 1