NOIP2012同余方程

#include<iostream>
#include<cstdio>
#include<string>
#include<cstring>
#include<cmath>
#include<algorithm>
#define ll long long
using namespace std;
ll euler_phi(ll x){
    ll m = (ll)sqrt(x+0.5);
    ll ans = x;
    for(int i = 2;i <= m;i++){
        if(x % i == 0){
            ans = ans / i * (i-1);
            while(x % i == 0) x /=  i;
        }
    }
    if(x > 1) ans = ans / x * (x-1);
    return ans;
}
ll q_mul(ll a,ll b,ll p){
    ll ans = 0;
    while(b){
        if(b&1){
            ans = (ans + a) % p;
            b--;
        }
        b >>= 1;
        a = (a + a) % p;
    }
    return ans;
}
ll q_pow(ll a,ll b,ll p){
    ll ans = 1;
    while(b){
        if(b&1){
            ans = q_mul(ans,a,p);
        }
        b >>= 1;
        a = q_mul(a,a,p);
    }
    return ans;
}
void exgcd(ll a,ll b,ll& d,ll& x,ll& y){
    if(b == 0){
        x = 1;
        y = 0;
        d = a;
        return;
    }
    exgcd(b,a%b,d,y,x);
    y -= (a/b)*x;
}
int phi[1000];
void phi_table(int n){
    for(int i = 2;i <= n;i++) phi[i] = 0;
    phi[1] = 1;
    for(int i = 2;i <= n;i++) if(!phi[i])
    for(int j = i;j <= n;j+=i){
        if(!phi[j]) phi[j] = j;
        phi[j] = phi[j] / i * (i-1);
    }
}
int main(){
    ll a,b,d,x,y;
    cin>>a>>b;
    cout<<q_pow(a,euler_phi(b)-1,b);
    return 0;
}