#define _USE_MATH_DEFINES
#include <algorithm>
#include <cstdio>
#include <functional>
#include <iostream>
#include <cfloat>
#include <climits>
#include <cstring>
#include <cmath>
#include <map>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <time.h>
#include <vector>
using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> i_i;
typedef pair<ll, int> ll_i;
typedef pair<double, int> d_i;
typedef pair<ll, ll> ll_ll;
typedef pair<double, double> d_d;
struct edge { int u, v, w; };

ll MOD = 1000000007;
ll _MOD = 1000000009;
double EPS = 1e-10;
int INF = INT_MAX / 2;

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