Codeforces 284A Cows and Primitive Roots [模拟题]

#include<iostream>
#include<fstream>
#include<map>
#include<vector>
#include<string>
#include<memory.h>
#include<cmath>
#include<algorithm>
#include<queue>
#define Min(a,b) (a<b?a:b)
#define Max(a,b) (a>b?a:b)
#define Abs(a) (a>0?(a):-(a))
#define llong long long int
using namespace std;
const int N=2005,M=100005,inf=0x7fffffff;
int n,m;
int main()
{
//freopen("1.txt","r",stdin);
while(scanf("%d",&n)!=EOF)
{
int ans=0;
for(int i =1;i<n;i++)
{
bool flag =true;
int now = 1;
for(int j=1;j<n-1;j++)
{
now = (now*i)%n;
if(now==1)
{
flag=false;
break;
}
}
now = (now*i)%n;
if(now != 1)
{
flag=false;
}
if(flag)
ans++;
}
printf("%d\n",ans);
}
return 0;
}