import std.conv;

import std.stdio;

​

interface Num {

    T num(T)();

}

​

class A : Num {

    T num(T)() {

        return 5.to!T;

    }

}

​

class B : Num {

    T num(T)() {

        return 2.to!T;

    }

}

​

void main() {

    auto a = new A();

    auto b = new B();

    Num somea = a;

    Num someb = b;

    writeln(a.num!int());

    writeln(somea.num!int());

    writeln(someb.num!int());

    writeln(somea.num!string());

    writeln(someb.num!string());

}