Innopolis University scientists continue to investigate the periodic table. There are n · m known elements and they form a periodic table: a rectangle with n rows and m columns. Each element can be described by its coordinates ( r , c ) ( 1 ≤ r ≤ n , 1 ≤ c ≤ m ) in the table. Recently scientists discovered that for every four different elements in this table that form a rectangle with sides parallel to the sides of the table, if they have samples of three of the four elements, they can produce a sample of the fourth element using nuclear fusion. So if we have elements in positions ( r 1 , c 1 ) , ( r 1 , c 2 ) , ( r 2 , c 1 ) , where r 1 ≠ r 2 and c 1 ≠ c 2 , then we can produce element ( r 2 , c 2 ) . Samples used in fusion are not wasted and can be used again in future fusions. Newly crafted elements also can be used in future fusions. Innopolis University scientists already have samples of q elements. They want to obtain samples of all n · m elements. To achieve that, they will purchase some samples from other laboratories and then produce all remaining elements using an arbitrary number of nuclear fusions in some order. Help them to find the minimal number of elements they need to purchase. The first line contains three integers n , m , q ( 1 ≤ n , m ≤ 200 000 ; 0 ≤ q ≤ min ( n · m , 200 000) ), the chemical table dimensions and the number of elements scientists already have. The following q lines contain two integers r i , c i ( 1 ≤ r i ≤ n , 1 ≤ c i ≤ m ), each describes an element that scientists already have. All elements in the input are different. Print the minimal number of elements to be purchased. For each example you have a picture which illustrates it. The first picture for each example describes the initial set of element samples available. Black crosses represent elements available in the lab initially. The second picture describes how remaining samples can be obtained. Red dashed circles denote elements that should be purchased from other