#include <sstream>
#include <string>
#include <vector>
#include <map>
#include <algorithm>
#include <iostream>
#include <utility>
#include <set>
#include <cctype>
#include <queue>
#include <stack>
#include <cstdio>
#include <cstdlib>
#include <cmath>

#define INF 1000000000

using namespace std;
typedef long long ll;

int A[64];

int main(void) {
    int N, M;
    cin >> N >> M;
    for (int i = 1; i <= N; i++) A[i] = i;
    for (int i = 0; i < M; i++) {
        int a;
        cin >> a;
        int index;
        for (int j = 1; j <= N; j++) {
            if (A[j] == a) {
                index = j;
                break;
            }
        }
        A[index] = 0;
        for (int j = 1; j <= N; j++) {
            if (A[j] <= a) A[j]++;
        }
    }
    for (int i = 1; i <= N; i++) {
        if (A[i] == 1) cout << i << endl;
    }
    return 0;
}