#include <iostream>

using namespace std;

const int MAXN =1000000;

int F[MAXN];
int main() {
	int n;
	cin >>n;
	int i = 0,p = 0, c = 0;
	while (___(1)___) {
		if(F[i] == 0 ) {
			if(___(2)___) {
				F[i] = 1;
				___(3)___;
			}
		   ___(4)___;
		}
		___(5)___;
	}
	int ans = -1;
	for (i =0 ; i < n; i++)
		if (F[i] == 0)
			ans = i;
	cout << ans << endl;
	return 0;
}