#include <iostream>

template<typename T>
struct transformer {
    int get() {
        return static_cast<T*>(this)->read();
    }
};

struct echot {
    template<typename Chain>
    struct chain : transformer< chain<Chain> > {
        Chain c;

        int read() {
            return c.get() + 1;
        }

        chain(Chain const& c):c(c) { }
    };
} echo;

struct noiset {
    template<typename Chain>
    struct chain : transformer< chain<Chain> > {
        Chain c;

        int read() {
            return c.get() * 2;
        }

        chain(Chain c):c(c) { }
    };
} noise;


template<typename T>
typename T::template chain<std::istream&> operator>>(std::istream& is, T) {
    return typename T::template chain<std::istream&>(is);
}

template<typename T, typename U>
typename U::template chain<T> operator>>(T t, U u) {
    return typename U::template chain<T>(t);
}

int main() {
    std::cout << (std::cin >> noise >> echo).get() << std::endl;
}

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