#include <stdio.h>
#include <map>
#include <queue>
#include <set>
#include <vector>
using namespace std;
int main(void){
long N;
scanf("%d", &N);
map<long, long> q_map;
q_map[0] = 0;
map<pair<long, long>, bool> line_map;
long line_count = 0;
long i;
for(long i=1; i<=N; i++){
long q_i;
q_i = (q_map[i-1]+i) % N;
//prlongf("%d\n", q_i);
if(q_i == 0){
//break;
}
if(q_map.count(i) == 0){
q_map[i] = q_i;
}
if(q_map[i-1] != q_i){
if(line_map.count(make_pair(q_map[i-1], q_i)) == 0 && line_map.count(make_pair(q_i, q_map[i-1])) == 0){
line_map[make_pair(q_map[i-1], q_i)] = true;
line_count += 1;
}
}
}
printf("%ld\n", line_count);
return 0;
}
