void Union(int x,int y)
{
	int rootx = find(x);
	int rooty = find(y);
	if(rootx == rooty) return ;
	if(rank[x]>rank[y]) Father[y] = x;
	else {
		Father[x] = y;
		if(rank[x] == rank[y]) rank[x]++;
	}
}

->
void Union(int x,int y)
{
	int rootx = find(x);
	int rooty = find(y);
	if(rootx == rooty) return ;
	Father[Father[x]] = Father[y];
}