package historycontest;
import java.util.Scanner;
public class _54_DSUPlant {
static int[] father;//必须要加static吗??
public static void main(String[] args) {
Scanner sc=new Scanner(System.in);
int m=sc.nextInt();
int n=sc.nextInt();
int k=sc.nextInt();
father=new int[m*n+1];
int count=0;
for (int i = 1; i <=m*n; i++) {
father[i]=i;
}
for (int i = 1; i <=k; i++) {
int x=sc.nextInt();
int y=sc.nextInt();
join(x, y);
}
for (int i = 1; i <=m*n; i++) {
if (father[i]==i) {
count++;
}
}
System.out.println(count);
}
//查找父结点
private static int find(int n) {
if(father[n]==n) {
return n;
}else {
father[n]=find(father[n]);
return father[n];
}
}
//连接结点
private static void join(int a,int b) {
if (find(a)!=find(b)) {
father[find(a)]=find(b);
}
}
}
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