#!/usr/bin/python
# -*- coding: utf-8 -*-

N,M = map(int, raw_input().split())
arys = map(int, raw_input().split())
ans = []

for i in xrange(1,N+1):
       	ans.append(int(i))

for i in arys:
       	tmp = ans.pop(i-1)
       	ans.insert(0,tmp)

print ans[0]