AFGJI FORTUNE TICKET

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Susan loves fortune numbers very much. We all know that fortune numbers are positive integers whose decimal record contains only the fortune digits 4 and 7. For example, numbers 47, 744, 4 are fortune and 5, 177, 42367 are not. Susan loves tickets very much. As we know, each ticket has a number that is a positive integer. Its length equals n (n is always even). Susan calls a ticket fortune if the

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solution.cppC++17

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