#include <iostream>
#include <algorithm>
using namespace std;
int main()
{
    int n, m;
    cin>>n>>m;
    vector<int> a(n);
    for(int i=1;i<=n;++i) a[i-1]=i;
    while (m--) {
        int t; cin>>t;
        rotate(begin(a), begin(a)+t-1, begin(a)+t);
    }
    cout<<a.front()<<endl;
}