What is lambda functions type? C++

See my code:

#include <iostream>
#include <typeinfo>

int main() {
    auto x = [](int a, int b) -> bool{return a<b;};
    std::cout<<typeid(decltype(x)).name()<<std::endl;
}

And this is printing Z4mainEUliiE_. Can anyone explain whay? And what is the actual type of x??