var cup = [0,0,0]
let N:Int = Int(readLine()!)!
cup[N - 1] = 1
let M:Int = Int(readLine()!)!
for _ in 1...M{
    let PQ = readLine()!.split(separator:" ").map{Int($0)!}
    let P = PQ[0] - 1
    let Q = PQ[1] - 1
    cup.swapAt(P, Q)
}
let index = cup.firstIndex(of: 1)!
print(index + 1)