func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     string num1, num2, num3;     int i, j, k, l, m, n, last, flag = 0;     cin >> num1;     num2 = num1;     num3 = num1;     l = num1.length();     last = num1.at(l - 1) - 48;     for (i = 0; i < l - 1; i++) {       m = num2.at(i) - 48;       if (m % 2 == 0 && m < last) {         swap(num2.at(i), num2.at(l - 1));         flag = 1;         cout << num2 << endl;         return 0;       }     }     if (flag == 0) {       for (i = l - 2; i >= 0; i--) {         m = num3.at(i);         if (m % 2 == 0 && last < m) {           swap(num3.at(i), num3.at(l - 1));           cout << num3 << endl;           return 0;         }       }     }     cout <<  -1  << endl;   }   