interface Bar<T, R> {
    fun something(input: T): R
}

class BarImpl1: Bar<Unit, String> {
    override fun something(input :Unit): String {
        return "Test"
    }
}

class BarImpl2: Bar<String, Int> {
    override fun something(input :String): Int {
        return input.length
    }
}

class Foo() {
    val list = mutableListOf<Bar<Any, Any>>()
    
    fun <T, R> addElem(bar: Bar<T, R>) {
        list.add(bar)
    }
}

fun main(args: Array<String>) {
    val foo = Foo()
    foo.addElem(BarImpl1())
    foo.addElem(BarImpl2())
    
    val output1 = foo.list[0].something(Unit)
    val output2 = foo.list[1].something(output1)
    println(output2)
}