#include<bits/stdc++.h>
using namespace std;
bool M1;
#define PI 3.14159265358979323846
#define sz(a) (int)a.size()
#define all(x) x.begin(),x.end()
#define ii pair<int,int>
#define iii pair<int,ii>
#define iv pair<ii,ii>
#define se second
#define fi first
#define ffi fi.fi
#define sfi se.fi
#define sse se.se
#define fse fi.se
#define lt(i, c, d) for(int i = c; i <= d; ++i)
#define fl(i, c, d) for(int i = d; i >= c; --i)
#define pb push_back
#define emb emplace_back
#define emf emplace_front
#define em emplace
#define look_memory cerr<<'\n'<<abs(&M2-&M1)/1024.0/1024<<'\n'
#define look_time   cerr << "TIME : " << clock() * 0.001 << "s" <<'\n'
const int N=1e6+5,lg=19,mod=1e9+7,inf=1e9,limi=1e6;
mt19937 rd(chrono::steady_clock::now().time_since_epoch().count());
int Rand(int u,int v){
 return u+rd()%(v-u+1);
}
int dx[]={1,0,-1,0,1,1,-1,-1};
int dy[]={0,-1,0,1,1,-1,1,-1};
int node,a[N],dp[N],lim[N],bit[N];
void update(int idx,int val){
    while(idx<=limi){
        bit[idx]+=val;
        idx+=idx&(-idx);
    }
}
int get(int idx){
    int res=0;
    while(idx>0){
        res+=bit[idx];
        idx-=idx&(-idx);
    }
    return res;
}
int getrange(int l,int r){
    if(l>=r)return 0;
    return get(r)-get(l-1);
}
int st[N*4];
void update(int id,int l,int r,int i,int val){
    if(r==l){
        st[id]=val;
        return ;
    }
    int mid=(r+l)>>1;
    if(i<=mid)update(id<<1,l,mid,i,val);
    else update(id<<1|1,mid+1,r,i,val);
    st[id]=min(st[id<<1],st[id<<1|1]);
}
int get(int id,int l,int r,int u,int v){
    if(l>v||r<u)return inf;
    if(u<=l&&r<=v)return st[id];
    int mid=(r+l)>>1;
    return min(get(id<<1,l,mid,u,v),get(id<<1|1,mid+1,r,u,v));
}
bool M2;
void solve(){
    cin >> node;
    for(int i=1;i<=node;++i)cin >> a[i],dp[i]=inf;
    dp[0]=0;
//    for(int i=1;i<=node;++i){
//        dp[i]=min(dp[i],dp[i-1]+1);
////        cout <<i<<'\n';
//        for(int j=i-1;j>=1;--j){
//            if(a[j]>a[j+1])break;
//            bool ok=true;
//            for(int x=1;x<=j;++x){
//                if(a[j]<a[x]&&a[x]<a[i])ok=false;
//            }
//            if(!ok)break;
//            dp[i]=min(dp[i],dp[j-1]+1);
////            cout <<j<<" ";
//        }
////        cout<<'\n';
//    }
    lim[1]=1;
    for(int i=2,vt=1;i<=node;++i){
        if(a[i-1]>a[i]){
            lim[i]=i;
            continue;
        }
        int j=lim[i-1];
        while(vt<=j){
//            cerr <<vt<<" "<<a[vt]<<'\n';
            update(a[vt],1);
            ++vt;
        }
        while(j<i&&getrange(a[j]+1,a[i]-1)){
            update(a[vt],1);
            ++vt;
            ++j;
        }
        lim[i]=j;
    }
    for(int i=1;i<=node;++i)update(1,1,node,i,inf);
    for(int i=1;i<=node;++i){
        update(1,1,node,i,dp[i-1]);
        dp[i]=get(1,1,node,lim[i],i)+1;
    }
//    for(int i=1;i<=node;++i)cerr <<a[i]<<" "<<lim[i]<<"\n";
    cout <<dp[node];
    cerr <<dp[node];
}
main()
{
  srand(time(0));
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
    #define task "a"
    if(fopen(task".inp","r")){
      freopen(task".inp","r",stdin);
      freopen(task".out","w",stdout);
    }
    int t=1;
 //   cin >> t;
while(t--){
    solve();cout<<'\n';
}
look_memory;
look_time;
}
컴파일 시 표준 에러 (stderr) 메시지
money.cpp:116:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
  116 | main()
      | ^~~~
money.cpp: In function 'int main()':
money.cpp:124:14: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  124 |       freopen(task".inp","r",stdin);
      |       ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
money.cpp:125:14: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  125 |       freopen(task".out","w",stdout);
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