#include <bits/stdc++.h>
#define FOR(i,a,b) for(int i = (a); i < (b); ++i)
#define REP(i,n) FOR(i,0,n)
#define sz(n) (int)(n).size()
using namespace std;
typedef long long ll;

int main() {
	int n, m;
	cin >> n >> m;
	vector<int> v;
	FOR(i, 1, n + 1) v.push_back(i);
	REP(i, m) {
		int a;
		cin >> a;
		v.insert(v.begin(), v[a - 1]);
		v.erase(v.begin() + a);
	}
	cout << v[0] << endl;
}