codeforces 4D. Mysterious Present

#include<cstdio>
#include<cstdlib>
#include<iostream>
#include<algorithm>
#include<vector>
#include<cmath>
#include<map>
#include<set>
#define M 5010
using namespace std;
struct type{
int w,h,c,t,p;
}En[M];
bool cmp(type a,type b){
if(a.w==b.w)
return a.h<b.h;
else return a.w<b.w;
}
int main(){
int n,cw,ch,i,j,k,s,maxi,x,w,h;
int a[M];
while(scanf("%d %d %d",&n,&cw,&ch)!=EOF){
x=1;
for(i=1;i<=n;i++){
scanf("%d %d",&w,&h);
if(w>cw&&h>ch){
En[x].w=w;
En[x].h=h;
En[x].c=1;
En[x].t=i;
En[x++].p=0;
}
}
if(x==1)printf("0\n");
else{
x--;
sort(En+1,En+1+x,cmp);
s=1;
k=En[s].c;
maxi=s;
for(i=s+1;i<=x;i++){
for(j=1;j<i;j++){
if(En[i].w>En[j].w&&En[i].h>En[j].h){
if(En[i].c<En[j].c+1){
En[i].c=En[j].c+1;
En[i].p=j;
}
}
}
if(En[i].c>k)maxi=i,k=En[i].c;
}
printf("%d\n",k);
j=maxi;i=0;
a[i++]=En[j].t;
while(En[j].p!=0){
j=En[j].p;
a[i++]=En[j].t;
}
i--;
while(i>0)printf("%d ",a[i--]);
printf("%d\n",a[i]);
}
}
return 0;
}