#include<iostream>
 
using namespace std;
 
class MathException : std::exception
{
public:
    MathException(std::string &&whatStr) noexcept : whatStr(std::move(whatStr)) { }
    MathException(const std::string &whatStr) noexcept : whatStr(whatStr) { }
    ~MathException() noexcept;
 
    const char* what() const noexcept override;
 
private:
    std::string whatStr;
};
 
const char* MathException::what() const noexcept
{
    return whatStr.c_str();
}
 
 
 
int main()
{
}
 

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