#include <iostream>
#include <math.h>
#include <algorithm>
#include <functional>
#include <vector>
#include <typeinfo>
#include <climits>
#include <ctype.h>
#include <string>
#include <stack>
using namespace std;
#define FOR(i, a, n) for (int i = a; i < n; i++)
#define REP(i, n) for(int i = 0; i < n; i++)
struct omt{omt(){ios::sync_with_stdio(false);cin.tie(0);}}star;

int main(){
    int n, m;
    cin >> n >> m;
    int A[m];
    REP(i, m){
        int tmp;
        cin >> tmp;
        A[i] = tmp - 1;
    }

    vector<int> C(n); //card
    REP(i, n) C[i] = i + 1;

    REP(i, m){
        C.insert(C.begin(), C[A[i]]);
        C.erase(C.begin() + A[i] + 1);
    }
    cout << C[0] << endl;

    return 0;
}