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% %     WHICH FLAG FOR THE NEW STATE?                                       % %
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%   A small new state has been founded in Europe. A passionate debate about   %
%   its national flag results in the following consensus: The flag consists   %
%   of three horizontal stripes, and the only acceptable colours for these    %
%   stripes are white, green, red and blue.                                   %
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%   The combination of these colours is subject to strict conditions. Most    %
%   importantly, no colour may be used for more than one stripe.              %
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%   It is impossible to use both white and green in the flag.                 %
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%   If green appears in the flag, then the upper stripe must be blue.         %
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%   The flag may have a red stripe, but only if it also has a white stripe.   %
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%   If the colour white is used, then the lower stripe must not be blue.      %
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%   If the colour blue is used, then the upper stripe must not be red.        %
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%   The flag committee receives three different design proposals, all of      %
%   which comply with the requirements. One ot them is finally accepted.      %
%   The other two have suggested the same colour for the lower stripe.        %
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%   What will be the colours of the new national flag?                        %
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%   Thus, there are several solutions, and one of them assigns a colour to    %
%   the lower stripe that is different from the colours assigned to the lower %
%   stripe by any other solutions. There is only one such solution, otherwise %
%   the problem would be underspecified.                                      %
%   The most natural approach is to determine all solutions and to let the    %
%   user select the correct one among them.                                   %
%   Alternatively, a system with sufficient functionality could determine     %
%   the solutions that are unique with respect to the colour of the lower     %
%   stripe.                                                                   %
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