SGU 102

基本題 就不詳細說明了

/*
 * GCA : "Computer is artificial subject absolutely,Math is God"
 */
#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <cmath>
#include <climits>
#include <vector>
#include <set>
#include <map>
#include <queue>
#include <cctype>
#include <utility>
#include <ctime>
using namespace std;
#ifdef DEBUG
#define VAR(a,b) __typeof(b) a=(b)
#define debug(...) printf("DEBUG: "),printf(__VA_ARGS__)
#else
#define VAR(a,b) __typeof(b) a=(b)
#define debug(...)
#endif
typedef unsigned int uint;
typedef long long int Int;
typedef unsigned long long int UInt;
#define Set(a,s) memset(a,s,sizeof(a))
#define Pln() printf("\n")
#define For(i,x)for(int i=0;i<x;i++)
#define CON(x,y) x##y
#define M 10005
#define PB push_back
#define oo INT_MAX
#define FOR(a,b) for(VAR(a,(b).begin());a!=(b).end();++a)
#define eps 1e-9
#define X first
#define Y second
inline bool xdy(double x,double y){return x>y+eps;}
inline bool xddy(double x,double y){return x>y-eps;}
inline bool xcy(double x,double y){return x<y-eps;}
inline bool xcdy(double x,double y){return x<y+eps;}
const Int mod=1000000007;
int n;
bool seize[M];
void init(){
    for(int i=2;i<M;i++){
        if(!seize[i]){
            for(int j=i+i;j<M;j+=i){
                seize[j]=1;
            }
        }
    }
}
int main() {
    ios_base::sync_with_stdio(0);
    init();

    while(~scanf("%d",&n)){
        int ans=n;
        for(int i=2;i<=n;i++){
            if(!seize[i]&&n%i==0){
                while(n%i==0)n/=i;
                ans=ans*(i-1)/i;
            }
        }
        printf("%d\n",ans);
    }


















}