fun main(args:Array<String>?): Unit {
    val state = readLine()!!.trim()
    var first = 0
    var second = 0
    if (state.first() == 'o') ++first else ++second
    for (i in 1 until state.length){
        if (state[i] != state[i - 1]){
            if (state[i] == 'o') ++first else ++second
        }
    }
    println(if (first >= second) "o" else "x")
}
