public interface UnitConverter {
	String toBaseUnit(String engUnit);
	Strnig toEngUnit(String baseUnit);
}

public class TemperatureConverter implements UnitConverter {
	public String toBaseUnit(String engUnit) {
		return engUnit * 2.5;
	}
	public String toEngUnit(String baseUnit) {
		return baseUnit / 2.5;
	}
}