import java.io.*;
import java.util.*;
import java.util.stream.*;

// 処理
class Process {
    private PrintWriter printWriter;
    private int   N;
    private int[] P;
    private int[] Q;

    Process(PrintWriter printWriter, int N, int[] P, int[] Q) {
        this.printWriter = printWriter;
        this.N = N;
        this.P = P;
        this.Q = Q;
    }

    // 結果を出力
    void printResult() throws IOException {
        int markedIndex = N;
        for(int i = 0; i < P.length; i++) {
            if(P[i] == markedIndex) {
                markedIndex = Q[i];
            }
        }
        
        printWriter.println(markedIndex);
    }
}

public class Main {
    public static void main(String[] args) throws IOException {
        var bufferedReader = new BufferedReader(new InputStreamReader(System.in));
        var printWriter    = new PrintWriter(new BufferedWriter(new OutputStreamWriter(System.out)));

        // 入力
        int N = Integer.parseInt(bufferedReader.readLine().trim());

        int M = Integer.parseInt(bufferedReader.readLine().trim());

        var input = new int[2];
        var P = new int[M];
        var Q = new int[M];
        for(int m = 0; m < M; m++) {
            input = Stream.of(bufferedReader.readLine().trim().split("[ ]+")).mapToInt(Integer::parseInt).toArray();
            P[m] = input[0];
            Q[m] = input[1];
        }
        
        // Process クラスで処理を行う
        var process = new Process(printWriter, N, P, Q);
        process.printResult();

        // 各ストリームを閉じる
        // 出力ストリームを閉じるときに標準出力に文字を出力する
        bufferedReader.close();
        printWriter.close();
    }
}