#include<bits/stdc++.h>
#define N 1000005
using namespace std;
int read()
{
	int x=0,f=1;char ch=getchar();
	while(ch<'0'||ch>'9'){if(ch=='-')f=-1;ch=getchar();}
	while(ch>='0'&&ch<='9'){x=x*10+ch-'0';ch=getchar();}
	return x*f;
}
const long double eps=1e-9;
int n;
bool vis[N];
long double V,M,len,ans;
struct mat
{
	double v,m,h;
	int id;
}s[N];
bool cmp(mat a,mat b){return a.h<b.h;}
bool check(double mid)
{
	int id=1;ans=0;//cout<<mid<<" ";
	while(s[id].v<mid)
	{
		mid-=s[id].v;
		id++;
	}
	ans+=(s[id].v-mid)*s[id].h;
	mid=len-(s[id].v-mid);
	if(mid<0)ans=s[id].h*len;
	else
	{
		id++;
		while(s[id].v<mid&&id<=n)
		{
			mid-=s[id].v;
			ans+=s[id].m;
			id++;
		}
		ans+=mid*s[id].h;
	}
	if(ans>=M/2-eps)return 1;
	return 0;
}
signed main()
{
//	freopen("bread.in","r",stdin);
//	freopen("bread.out","w",stdout);
	n=read();V=0;M=0;ans=0;
	for(int i=1;i<=n;i++)
	{
		s[i].v=read(),s[i].id=i,V+=s[i].v,vis[i]=0;
		s[i].m=read(),s[i].h=s[i].m/s[i].v,M+=s[i].m;
	}
	sort(s+1,s+1+n,cmp);
	len=V/2;
	double l=0,r=len,mid;
	for(int i=1;i<=250;i++)
	{
		mid=(l+r)/2;
		if(check(mid))r=mid;
		else l=mid;
	}
	vis[n+1]=vis[n+2]=1;
	int id=1;
	while(s[id].v<mid)
	{
		mid-=s[id].v;
		id++;
	}
	ans+=(s[id].v-mid)*s[id].h;
	cout<<"2\n";
	printf("%d %.14f\n",s[id].id,mid/s[id].v);
	double p=len/(s[id].v-mid);
	mid=len-(s[id].v-mid);
	if(mid<0)
	{
		vis[n+2]=0;
		printf("%d %.14f\n",n+1,p);
	}
	else
	{
		id++;
		while(s[id].v<mid&&id<=n)
		{
			mid-=s[id].v;
			ans+=s[id].m;
			vis[s[id].id]=1;
			id++;
		}
		ans+=mid*s[id].m;
		printf("%d %.14f\n",s[id].id,(s[id].v-mid)/s[id].v);
	}
	int num=0;
	for(int i=1;i<=n+2;i++)if(vis[i])num++;
	cout<<num<<"\n";
	for(int i=1;i<=n+2;i++)if(vis[i])cout<<i<<" ";cout<<"\n";
	return 0;
}