Write a C++ program to create a new string taking 3 characters from the middle of a given string at least 3

#include <iostream>
using namespace std;

string test(string s1)
        {
           return s1.substr((s1.length() - 1) / 2 - 1, 3);
        }
         
int main() 
 {
  cout << test("Hello") << endl;  
  cout << test("Python") << endl; 
  cout << test("abc") << endl; 
  return 0;    
}