1 #include <iostream>
 2 #include <cstdio>
 3 #include <cstring>
 4 using namespace std;
 5 
 6 const int inf = 0x3f3f3f;
 7 const int maxn = 30011;
 8 int dp[maxn];
 9 
10 int main(){
11     int a, b, n;
12     int ans;
13     bool flag;
14     while(scanf("%d", &n)!=EOF){
15         ans = 0;
16         while(n--){
17             a = inf;
18             scanf("%d", &b);
19             flag = false;
20             int temp;
21             for(int i = 0; i < ans; ++i){       //如果可以选出高度差最小的拦截系统
22                 if(b <= dp[i] && a > dp[i]-b){
23                     a = dp[i] - b;
24                     temp = i;
25                     flag = true;
26                 }
27             }
28 
29             if(!flag){          //更新拦截系统
30                 dp[ans] = b;
31                 ++ans;
32             }
33             else{
34                 dp[temp] = b;
35             }
36         }
37 
38         printf("%d\n", ans);
39     }
40     return 0;
41 }