#include // #include using namespace std; // using bigint = boost::multiprecision::cpp_int; template using min_priority_queue = priority_queue,greater>; random_device seed_gen; mt19937 engine(seed_gen()); int64_t get_time_ns(){ struct::timespec t; clock_gettime(CLOCK_MONOTONIC, &t); return t.tv_sec * int64_t(1'000'000'000) + t.tv_nsec; } int main() { int n, k; cin >> n >> k; int ans; if(k <= n) ans = 1 << (n - k); else ans = 0; cout << ans << endl; return 0; }