#include <iostream>
#include <list>

#define FORR(i,b,e) for(int i=(b);i<(int)(e);++i)
#define FOR(i,e) FORR(i,0,e)
#define dump(var) cerr << #var ": " << var << "\n"
#define dumpc(con) for(auto& e: con) cerr << e << " "; cerr<<"\n"

typedef long long ll;
typedef unsigned long long ull;

const double EPS = 1e-6;
const int d4[] = {0, -1, 0, 1, 0};

using namespace std;


int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);

    int N, M;
    cin >> N >> M;

    list<int> card;
    FOR(i, N) card.push_back(i+1);
    
    FOR(i, M) {
        int A;
        cin >> A;
        A--;
        auto c = card.begin();
        while (A--) c++;
        int n = *c;
        card.erase(c);
        card.push_front(n);
    }
    cout << card.front() << endl;

    return 0;
}