#include<iostream>
#include<algorithm>
#include<vector>
#include<string>
#include<utility>
#include<map>
#include<set>
#include<queue>
#include<stack>
#include<functional>
#include<math.h>
#include<random>
#include <bitset>
using namespace std;
//#define N (1000000000+7)
#define N 998244353
#define INF 1e16
typedef long long ll;
typedef pair<int,int> P;
typedef pair<int,P> Q;

const int inf = (int)1e9; 

ll gcd(ll a, ll b) {
	if (b > a) {
		ll tmp = b;
		b = a;
		a = tmp;
	}
	if (a%b == 0)return b;
	else return gcd(b, a%b);
}


int main(void){
	int n,m;
	cin>>n>>m;
	vector<int>A(n);
	for(int i=1;i<=n;i++)A[i-1]=i;
	for(int i=0;i<m;i++){
		int a;
		cin>>a;
		vector<int>b(n);
		b[0]=A[a-1];
		ll X = A[a-1];
		int index = 0;
		for(int i=1;i<n;){
			if(X==A[index]){
				index++;
				continue;
			}
			else{
				b[i]=A[index];
				index++;
				i++;
			}
		}
		A = b;
	}
	cout<<A[0]<<endl;
	return 0;
}