#include <iostream>
#include <algorithm>
#include <deque>
using namespace std;

class range {private: struct I{int x;int operator*(){return x;}bool operator!=(I& lhs){return x<lhs.x;}void operator++(){++x;}};I i,n;
public:range(int n):i({0}),n({n}){}range(int i,int n):i({i}),n({n}){}I& begin(){return i;}I& end(){return n;}};

int main(void) {
  int n, m; scanf("%d%d", &n, &m);
  deque<int> deq(n);
  for(int i : range(n)) { deq[i] = i + 1; }
  for(int i : range(m)) {
    int ai; scanf("%d", &ai); ai--;
    int val = deq[ai];
    deq.erase(deq.begin() + ai);
    deq.push_front(val);
  }
  printf("%d\n", deq.front());
  return 0;
}