#include <iostream>
#include <algorithm>
#include <vector>
#include <string>
using namespace std;
typedef long long LL;

int main(){
    LL N, M;
    cin >> N >> M;
    vector<int> card(N);
    for(int i = 0; i < N; i++){
        card[i] = i+1;
    }
    for(int i = 0; i < M; i++){
        int a;
        cin >> a;
        int val = card[a-1];
        card.erase(card.begin() + a-1);
        card.insert(card.begin(), val);
    }
    cout << card[0] << endl;
    return 0;
}