var
A, B, C: integer;
A_1, B_1, C_1: boolean;
begin
write('Введите A, B и C: ');
read(A, B, C);
A_1 := (A > 0) and (B <= 0) and (C <= 0);
B_1 := (A <= 0) and (B > 0) and (C <= 0);
C_1 := (A <= 0) and (B <= 0) and (C > 0);
writeln('Ровно одно из чисел A, B, C положительное - ', A_1 xor B_1 xor C_1);
end.