let inpt = readLine()!.split(separator: " ").map{Int($0)!}
let itemCount = inpt[0]
let shuffCount = inpt[1]

var cards = [Int]()
for i in 1...itemCount {
    cards.append(i)
}

let shuffle = readLine()!.split(separator: " ").map{Int($0)! - 1}

for sh in shuffle {
    let tmp = cards[sh]
    cards.remove(at: sh)
    cards.insert(tmp, at: 0)
}

print(cards.first!)