#include <bits/stdc++.h> 

using i64 = long long; 
using u64 = unsigned long long; 
using u32 = unsigned; 

using u128 = unsigned __int128; 
using i128 = __int128; 

void solve() {
	int N, M; std::cin >> N >> M;
	std::vector<int> A(N);
	std::iota(A.begin(), A.end(), ++ A[0]);
	
	for(int i = 0; i < M; i ++) {
		int a; std::cin >> a;
		std::rotate(A.begin(), A.begin() + a - 1, A.begin() + a);
	}

	std::cout << A[0];

} 

int main() { 
	std::ios::sync_with_stdio(false); 
	std::cin.tie(nullptr); 

	int T = 1; 
	//std::cin >> T; 

	while (T--) { 
		solve(); 
	} 
	return 0; 
}