#include <iostream>
#include <list>
using namespace std;
 
int main(){
	int N, M;
	cin >> N >> M;
	list<int> cards;
	for(int i = 0; i < N; i++){
		cards.push_back(i + 1);
	}
	for(int i = 0; i < M; i++){
		int process;
		cin >> process;
		auto iterator = cards.begin();
		for(int j = 0; j < process - 1; j++){
			iterator++;
		}
		cards.push_front(*iterator);
		cards.erase(iterator);
	}
	auto iterator = cards.begin();
	cout << *iterator << endl;
}