func_code_string: #include <bits/stdc++.h>   using namespace std;   const long long N = 1e6 + 5;   const long long INF = 1e9 + 7;   long long n, ans = INF;   string s;   int main() {     ios_base::sync_with_stdio(false);     cin.tie(NULL);     cout.tie(NULL);     cin >> s;     long long n = s.size();     for (long long mask = 1; mask < 1 << n; mask++) {       long long t = 0;       bool check = true;       for (long long i = 0; i < n; i++)         if (mask >> i & 1) {           t = t * 10 + s[i] -  0 ;           if (t == 0 && s[i] ==  0 ) check = false;         }       long long tt = sqrt(t);       if (tt * tt == t && tt != 0 && check)         ans = min(ans, n - __builtin_popcount(mask));     }     cout << (ans == INF ? -1 : ans);     return 0;   }   