func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     int n;     cin >> n;     if (n <= 2)       cout <<  -1 ;     else if (n == 3)       cout <<  210 ;     else {       int mod = 1;       for (int i = 1; i < n; ++i) mod = (mod * 10) % 210;       if (n > 3) cout <<  1 ;       for (int i = 0; i < n - 4; ++i) cout <<  0 ;       if (210 - mod < 100) cout <<  0 ;       cout << 210 - mod;     }   }   