#include <iostream> #include <cmath> #include <vector> using namespace std; // 判断一个数是否为素数 bool isPrime(int num) { if (num < 2) return false; if (num == 2) return true; if (num % 2 == 0) return false; for (int i = 3; i <= sqrt(num); i += 2) { if (num % i == 0) return false; } return true; } // 判断一个素数是否为超级素数 bool isSuperPrime(int num) { int temp = num; while (temp > 0) { if (!isPrime(temp)) return false; temp /= 10; } return true; } int main() { int n; cin >> n; int count = 0; for (int i = 10; i <= n; i++) { if (isPrime(i) && isSuperPrime(i)) { count++; } } cout << count << endl; return 0; }