func_code_string: #include <bits/stdc++.h>   using namespace std;   const int LIMIT = 1000;   long long n;   long long sqrt2(long long n) {     long long r = max((long long)sqrt(n) + 1, 0LL);     while (r * r > n) {       r--;     }     return r;   }   int sum(long long n) {     int result = 0;     while (n) {       result += n % 10;       n /= 10;     }     return result;   }   int main() {     cin >> n;     for (long long s = 1; s < LIMIT; ++s) {       long long d = s * s + 4 * n;       long long r = sqrt2(d);       if (r * r == d && (r - s) % 2 == 0) {         long long x = (r - s) / 2;         if (sum(x) == s) {           cout << x << endl;           return 0;         }       }     }     cout << -1 << endl;     return 0;   }   