[BOJ/Java] 20361 일우는 야바위꾼

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.StringTokenizer;

public class Main {

	static BufferedReader br;
	static StringBuilder sb;
	static StringTokenizer st;
	static int T, tc, n, x, k, i, swap1, swap2;
	static boolean cups[], tmp;

	public static void main(String[] args) throws Exception {
		br = new BufferedReader(new InputStreamReader(System.in));
		sb = new StringBuilder();

        st = new StringTokenizer(br.readLine());
        n = Integer.parseInt(st.nextToken());
        x = Integer.parseInt(st.nextToken());
        k = Integer.parseInt(st.nextToken());
        cups = new boolean[n + 1];
        cups[x] = true;
        for (i = 0; i < k; i++) {
            st = new StringTokenizer(br.readLine());
            swap1 = Integer.parseInt(st.nextToken());
            swap2 = Integer.parseInt(st.nextToken());
            tmp = cups[swap1];
            cups[swap1] = cups[swap2];
            cups[swap2] = tmp;
        }
        for (i = 1; i <= n; i++) {
            if (cups[i]) {
                sb.append(i);
                break;
            }
        }
		br.close();
		System.out.println(sb);
	}
}