#include<iostream>
#include<string>
#include<algorithm>
#include<vector>
#include<queue>
#include<map>
#include<math.h>
#include<iomanip>
#include<set>
#include<numeric>
#include<cstring>
#include<cstdio>
#include<functional>
#include<bitset>
#include<limits.h>
#include<cassert>
#include<iterator>
#include<complex>
#include<stack>
using namespace std;
#define lint long long int
/*
vector<char>al(26);
al = {'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z'};
vector<char>AL(26);
AL = {'A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z'};
*/

int main() {
	int N, M;
	cin >> N >> M;
	vector<int>veca(M);
	for (int ia = 0; ia < M; ia++) {
		cin >> veca.at(ia);
	}
	vector<int>vec1(N);
	for (int ib = 0; ib < N; ib++) {
		vec1.at(ib) = ib + 1;
	}
	vector<int>vec2(N);
	for (int ic = 0; ic < N; ic++) {
		vec2.at(ic) = vec1.at(ic);
	}
	for (int id = 0; id < M; id++) {
		for (int ie = 0; ie < veca.at(id)-1; ie++) {
			vec2.at(ie + 1) = vec1.at(ie);
		}
		vec2.at(0) = vec1.at(veca.at(id) - 1);
		for (int ig = 0; ig < N; ig++) {
			vec1.at(ig) = vec2.at(ig);
		}
	}
	cout << vec1.at(0) << endl;
}