#include<iostream>
#include<stdio.h>
#include<vector>
#include<algorithm>
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;
    }
    vector<int> shuf(m);
    for(int i=0; i<m; i++){
        cin>> shuf[i];
    }

    int fig;
    for(int i=0; i<m; i++){
        fig = card[shuf[i]-1];
        for(int j=shuf[i]-1; j>0; j--){
            card[j] = card[j-1];
        }
        card[0] = fig;
    }

    cout<< card[0]<< endl;
    return 0;
}