#include <iostream>
#include <vector>
#include <algorithm>
#include <math.h>

#define ALL(x) (x).begin(),(x).end()
#define REP(i,n) for(int i = 0;i < (n);i++)
#define PI 3.14159265359

using namespace std;

int main(){
    int n,m;
    cin >> n >> m;
    vector<int> num(n);
    for(int i = 0;i <= n;i++)num[i] = i;
    REP(i,m){
        int a,s;
        cin >> a;
        s = num[a];
        for(int j = a;j > 0;j--){
            num[j] = num[j-1];
        }
        num[1] = s;
        
    }
    cout << num[1] << endl;
    return 0;
}