#include <boost/date_time/posix_time/posix_time.hpp>
#include <boost/date_time/gregorian/gregorian.hpp>
#include <iostream>
using namespace std;
	using boost::gregorian::date;
    using boost::posix_time::ptime;
    
    date f(date d){
        return next_weekday(d,  boost::date_time::weekdays::Friday);
    }
    
int main() {
	// your code goes here
	return 0;
}