题意：
a的p次方p取模等于a，且p不是素数，就输出yes；
#include<iostream>
#include<cstdio>
#include<algorithm>
#include<cmath>
#include<cstring>
#define ll long long
using namespace std;
ll powermod(ll a,ll b,ll c){
ll ans=1;
a = a % c;
while(b>0){
if(b%2) ans = (ans * a) %c;
b = b/2;
a = (a * a)%c;
}
return ans;
}
bool jud(ll x){
ll te = sqrt(x);
for(int i =2 ;i <= te; i++)
if(!(x % i)) return 1;//x不是素数返回true
return 0;
}
int main(){
ll p,a;
while(scanf("%I64d%I64d",&p,&a)){
if(p == 0&&a == 0) break;
ll te = powermod(a, p, p);
if(te == a && jud(p)) puts("yes");
else puts("no");
}
return 0;
}
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