#include<iostream>
#include<vector>
#include<algorithm>
#define REP(i,a) for(i=0;i<a;i++)
using namespace std;

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