import java.util.function.Function;
import java.util.function.Supplier;
import java.util.function.UnaryOperator;

public class Main<T> {
    String map(UnaryOperator<T> mapper) {
        return "op";
    }

    <R> String map(Function<T, R> mapper) {
        return "fn";
    }

    public static void main(String args[]) {
        new Main<Integer>().map(i -> "");
    }
}