同余方程可变换
x≡a/b (%p)
==> x*b≡a (%p)
==> bx+p*y=a
==> x=x0+p/gcd(b,p)
#include<bits/stdc++.h> using namespace std; namespace{ template<typename T> inline void read(T &s){ T f=1;s=0;char ch=getchar(); for(;!isdigit(ch);ch=getchar()) f=-1; for(;isdigit(ch);ch=getchar()) s=((s<<1)+(s<<3)+(ch^48))%19260817; } } #define fio ios::sync_with_stdio(false);cin.tie(0);cout.tie(0); #define ll long long int exgcd(int a,int b,ll& x,ll& y){ // if(b==0){ x=1;y=0; return a; } int res=exgcd(b,a%b,x,y); ll t=x; x=y; y=t-a/b*y; return res; } ll a,b,x,y; int main(){ read(a);read(b); //cout << a << b; int p=19260817; ll g_cd=exgcd(b,p,x,y); if(a%g_cd){ cout << "Angry!\n";return 0; } x=(x%p+p)%p; (x*=a)%=p; cout << x; return 0; }