[Poi2008]海报PLA

/*program from Wolfycz*/
#include<cmath>
#include<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>
#define inf 0x7f7f7f7f
using namespace std;
typedef long long ll;
typedef unsigned int ui;
typedef unsigned long long ull;
inline int read(){
    int x=0,f=1;char ch=getchar();
    for (;ch<‘0‘||ch>‘9‘;ch=getchar())  if (ch==‘-‘)    f=-1;
    for (;ch>=‘0‘&&ch<=‘9‘;ch=getchar())    x=(x<<1)+(x<<3)+ch-‘0‘;
    return x*f;
}
inline void print(int x){
    if (x>=10)     print(x/10);
    putchar(x%10+‘0‘);
}
const int N=2.5e5;
int stack[N+10],top;
int main(){
    int n=read(),same=0;
    for (int i=1;i<=n;i++){
        int x=read(),y=read();
        while (top&&y<=stack[top]){
            if (y==stack[top])  same++;
            top--;
        }
        stack[++top]=y;
    }
    printf("%d\n",n-same);
    return 0;
}