#include <cstdio>
#include <iostream>
#include <sstream>
#include <fstream>
#include <iomanip>
#include <algorithm>
#include <cmath>
#include <string>
#include <vector>
#include <list>
#include <queue>
#include <stack>
#include <set>
#include <map>
#include <bitset>
#include <numeric>
#include <limits>
#include <climits>
#include <cfloat>
#include <functional>
using namespace std;

int main()
{
    int n, m;
    cin >> n >> m;

    vector<int> card(n);
    for(int i=0; i<n; ++i)
        card[i] = i + 1;

    while(--m >= 0){
        int a;
        cin >> a;
        rotate(card.begin(), card.begin() + a - 1, card.begin() + a);
    }
    cout << card[0] << endl;

    return 0;
}