#include <stdio.h>

int main(void) {
	int N, M, i, j, A[100000], C[51], num;
	scanf("%d%d", &N, &M);
	for(i = 1;i <= M;i++){
		scanf("%d", &A[i]);
	}
	for(i = 1;i <= 50;i++){
		C[i] = i;
	}
	for(i = 1;i <= M;i++){
		num = C[A[i]];
		for(j = 0;j <= A[i];j++){
			C[A[i] - j] = C[A[i] - j - 1];
		}
		C[1] = num;
	}
	printf("%d\n", C[1]);

	return 0;
}