#include <iostream> #include <vector> #include <set> #include <queue> #include <algorithm> #include <string> #include <fstream> #include <cctype> #include <iomanip> #include <cmath> #include <cstring> #include <map> #include <bitset> #include <stack> /* //c++11 #include <unordered_map> #include <unordered_set> #include <tuple> */ using namespace std; //ifstream fin("1.in"); //ofstream fout("1.out"); int solve() { int n; cin>>n; if(n == 2) return 1; if(n == 3) return 2; if(n == 4) return 2; for(int i = 2; i <= sqrt(n); i++) if(n%i ==0) return 0; return n-1; } int main() { //freopen("1.in","r",stdin); //freopen("1.out","w",stdout); cout<<solve(); return 0; } //FILE!!!