func_code_string: #include <bits/stdc++.h>   using namespace std;   int a, b;   int main() {     cin >> a >> b;     if (a > b + 1 or (a + 1) * 2 < b) {       cout << -1;       return 0;     }     string s;     s.push_back( 1 );     int n = a + b, ok = 1;     for (int i = 1; i < n; i++) {       if (ok and b > a) {         s.push_back( 1 );         ok = 0;         b--;       } else {         if (s[i - 1] ==  0 ) {           ok = 1;           s.push_back( 1 );           b--;         } else {           s.push_back( 0 );           a--;         }       }     }     if (a == 1) s.pop_back(), s =  0  + s;     cout << s;   }   