from collections import *
from itertools import *
from functools import *
from heapq import *
import sys,math
input = sys.stdin.readline

N,M = map(int,input().split())
A = list(map(int,input().split()))
X = [i+1 for i in range(N)]

for a in A:

    a -= 1
    X = [X[a]] + X[:a] + X[a+1:]
print(X[0])