C++ :

#include<cstdio>
int n,x1,y1,x2,y2;
int a[200005][2],b[100005],ans=2147483647;
int min(int a,int b){
	return a>b?b:a;
}
void swap(int &a,int &b){
	int t = a;
	a = b;
	b = t;
	return ;
}
int qsort(int x,int y)
{
	int r=x,l=y,midz=a[(x+y)>>1][0];
	while(r<=l)
	{
		while(a[r][0]<midz)r++;
		while(a[l][0]>midz)l--;
		if(r<=l)
		{
			swap(a[r][0],a[l][0]);
			swap(a[r][1],a[l][1]);
			r++;l--;
		}
	}
	if(x<l) qsort(x,l);
	if(r<y) qsort(r,y);
	return 0; 
}
int main()
{
	//freopen("missile.in","r",stdin);
	//freopen("missile.out","w",stdout);
	scanf("%d%d%d%d",&x1,&y1,&x2,&y2);
	scanf("%d",&n);
	for(int i=1;i<=n;i++)
	{
		int x,y;
		scanf("%d%d",&x,&y);
		a[i][0]=(x1-x)*(x1-x)+(y1-y)*(y1-y);
		a[i][1]=(x2-x)*(x2-x)+(y2-y)*(y2-y);
	}
	qsort(1,n);
	int mx = 0; 
	for(int i = n;i >= 1;i--)
	{
		if(mx < a[i][1]) mx = a[i][1];
		b[i] = mx;
	}
	for(int i=0;i<=n;i++)
		ans=min(b[i+1]+a[i][0],ans);
	printf("%d",ans);
	return 0;
}