John 有 $N$（$1\le N\le25{,}000$）矩形棚，邊平行 $X,Y$ 軸，頂點整數座標在 $0..1,000,000$。棚不重疊，可共角、邊。
今年更多牛要擠奶，想擴建。不與任何棚共角或牆時可擴，即四牆皆能外推至少一小段而不碰其他棚。兩棚共角則兩者皆不能擴。
求可擴建棚數。
第 1 行：整數 $N$。
第 $2..N+1$ 行：空格分隔 $A,B,C,D$，左下 $(A,B)$，右上 $(C,D)$。
第 1 行：可擴建棚數，整數。
5
0 2 2 7
3 5 5 8
4 2 6 4
6 1 8 6
0 0 8 12說明
範例說明：
5 棚，第一左下 $(0,2)$、右上 $(2,7)$，其餘類似。
僅輸入前兩棚可擴。其餘各至少接觸另一棚。
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