#include <iostream>
#include<string>
using namespace std;

int main() 
{
   string str ="I am an alien";
   int len = str.length();
   cout<<"Count: "<<len<<endl;
   
   int txt = str.find("to");
   cout<<"Count :"<<txt<<endl;
   
   string sub = str.substr(4,5);
   cout<<sub;
   string a = "Hello";
   a.append("bye");
   cout<<a<<endl;
   string b = "Hello";
   b.push_back('o');
   b.pop_back('H');
   return 0;
}