// iostream is too mainstream
#include <cstdio>
// bitch please
#include <iostream>
#include <algorithm>
#include <cstdlib>
#include <vector>
#include <set>
#include <map>
#include <queue>
#include <stack>
#include <list>
#include <cmath>
#include <iomanip>
#define dibs reserve
#define OVER9000 1234567890
#define ALL_THE(CAKE,LIE) for(auto LIE =CAKE.begin(); LIE != CAKE.end(); LIE++)
#define tisic 47
#define soclose 1e-8
#define chocolate win
// so much chocolate
#define patkan 9
#define ff first
#define ss second
#define abs(x) ((x < 0)?-(x):x)
#define uint unsigned int
#define dbl long double
using namespace std;
// mylittledoge
 
int main() {
	cin.sync_with_stdio(0);
	cin.tie(0);
	int N;
	cin >> N;
	int cnt =N-1;
	for(int k =2; k*k <= N; k++) if(N%k == 0) {
		cnt =N-N/k;
		break;}
	cout << cnt << "\n";
	return 0;}
 
// look at my code
// my code is amazing
 

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