#include <iostream>
using namespace std;
int gcd(int x,int y);//最大公約數函式
int ectgcd(int c,int d);//乘法逆元函式
int main()
{
    int a,b,g;
    cin>>a>>b;
    if(gcd(a,b)!=1)
    {
       cout<<"兩數之間不存在乘法逆元"<<endl;
    }
    else
    {
        g=ectgcd(a,b);
        cout<<"乘法逆元是："<<g;
    }
    return 0;
}
int gcd(int x,int y)
{
    int m;
    while(y!=0)
    {
        m=x%y;
        x=y;
        y=m;
    }
        return (x);

}
int ectgcd(int c,int d)
{
    int r0,r1,y,s,t,s0,s1,t0,t1,q,r;
    r0=d;
    r1=c%d;
    if(r1==1)
    {
        y=1;
    }
    else
    {
        s0=1;
        s1=0;
        t0=0;
        t1=1;
        while(r0%r1!=0)
        {
            q=r0/r1;
            r=r0%r1;
            r0=r1;
            r1=r;
            s=s0-q*s1;
            s0=s1;
            s1=s;
            t=t0-q*t1;
            t0=t1;
            t1=t;
            if(r==1)
            {
                if(t>0)
                {
                    y=t;
                }
                else if(t<0)
                {
                    y=t+d;

                }

            }
        }
    }
    return y;
}