func_code_string: #include <bits/stdc++.h>   using namespace std;   template <class T>   inline T gcd(T a, T b) {     return b == 0 ? a : gcd(b, a % b);   }   template <class T>   inline T lcm(T a, T b) {     return (a / gcd(a, b)) * b;   }   int main() {     int n;     int d = 210;     cin >> n;     if (n < 3) {       cout << -1 << endl;       return 0;     }     if (n == 3) {       cout << 210 << endl;       return 0;     }     cout << 1;     int m = 1;     for (int i = 0; i < (n - 1); i++) {       m *= 10;       m %= 210;       if (i < n - 4) cout << 0;     }     int r = 210 - m;     if (r < 10)       cout << 00 << r << endl;     else if (r < 100)       cout << 0 << r << endl;     else       cout << r << endl;     return 0;   }   