백준 2839 c++

#include <iostream>

#include <algorithm>

using namespace std;

class Count {

private:

int kilo;

int three;

int flag;

public:

Count(int n) : kilo(n) {

flag = 0;

three = 0;

}

void countthree() {

if (kilo % 3 == 0)

three = kilo / 3;

}

void countthreeandfive() {

int f;

f = kilo / 5;

while (f > 0) {

if ((kilo - f * 5) % 3 == 0) {

kilo = f + (kilo - f * 5) / 3;

flag = 1;

return;

}

else

f -= 1;

}

}

void printans() {

if ((flag == 0) && (three == 0)) {

cout << "-1";

}

else

if (three != 0) {

cout << min(kilo, three);

}

else

cout << kilo;

}

};

int main(void) {

int n;

cin >> n;

Count c(n);

c.countthree();

c.countthreeandfive();

c.printans();

}