fun main(){
    val b = readLine()!!.split(" ").map(String::toInt)
    var i = 0
    if(b[i] == 2){
    println(1)
        return
    }
    while(b[i+1] - 1 == b[i] ){
        i++
        if(i==8) break;
    }
    println(b[i] + 1)
}