#include #define ALL(v) std::begin(v),std::end(v) using lint=long long; using lubl=long double; int main(){ std::cin.tie(nullptr);std::ios_base::sync_with_stdio(false); std::cout.setf(std::ios_base::fixed);std::cout.precision(15); lint lg=19; std::vectorninepow(lg); ninepow.at(0)=1; for(lint i=1;ia; for(lint i=x;i;i/=10)a.push_back(i%10); std::reverse(ALL(a)); lint n=a.size(); lint ans=0; for(lint i=1;i>n; if(n<=billion){ std::cout<<0<<'\n'; return 0; } lint b=n/(billion+1); lint ans=f(b); std::cout<