// Generic structs - Box<T> and Pair<T, U>
import Std::Io::{PrintLine, PrintInt};

struct Box<T> {
    value: T,
}

struct Pair<T, U> {
    first: T,
    second: U,
}

func Main() -> int {
    let b: Box<int> = Box<int> { value: 42 };
    PrintLine("Box value:");
    PrintInt(b.value);
    PrintLine("");
    
    let p: Pair<int, String> = Pair<int, String> { first: 10, second: "hello" };
    PrintLine("Pair first:");
    PrintInt(p.first);
    PrintLine("");
    
    return 0;
}