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

int main() 
{
    vector <int> v = {1, 2, 3, 4, 5, 6};
    vector <int> :: iterator ptr = v.begin();
    advance(ptr, 3);
    int count = 0;
    while(ptr != v.end())
    {
        count++;
         ptr++;
    }
    cout << count;
    return 0;
}