import strutils, sequtils

proc main =
    let N, M = parseInt readLine stdin
    var cups = "/xxx/"
    cups[N] = 'o'
    
    for i in 0 ..< M:
      var P, Q: int
      (P, Q) = map(split readLine stdin, parseInt)
      swap(cups[P], cups[Q])
    
    echo find(cups, 'o')

main()