20 lines
330 B
ObjectPascal
20 lines
330 B
ObjectPascal
var s:char;
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t:integer;
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begin{main}
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assign(input,'stack.in');
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reset(input);
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read(s);
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repeat
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case s of
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'(':inc(t);
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')':dec(t);
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end;
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read(s);
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until s='@';
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close(input);
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assign(output,'stack.out');
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rewrite(output);
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if t=0 then writeln('YES')
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else writeln('NO');
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close(output);
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end. |