package main

import . "fmt"

func main() {
	var n, m int
	Scan(&n,&m)
	c:=make([]int,n)
	for i:=range c {
		c[i]=i+1
	}
	for i:=0;i<m;i++ {
		var a int
		Scan(&a)
		a--
		x:=make([]int,0,n)
		c=append(append(append(x, c[a]),c[:a]...),c[a+1:]...)
	}
	Println(c[0])
}