#include<bits/stdc++.h>
using namespace std;
using Int = long long;
//INSERT ABOVE HERE
signed main(){
  Int n,m;
  cin>>n>>m;
  vector<Int> a(n);
  iota(a.begin(),a.end(),0);
  for(Int i=0;i<m;i++){
    Int x;
    cin>>x;
    x--;
    Int k=a[x];
    a.erase(a.begin()+x);
    a.insert(a.begin(),k);
  }
  cout<<a[0]+1<<endl;
  return 0;
}