#include<iostream>
#include<algorithm>
#include<cstring>

using namespace std;
typedef long long LL;


int exgcd(LL a,LL b,LL &x,LL &y)
{
    if(!b)
    {
        x=1,y=0;
        return a;
    }
    LL d=exgcd(b,a%b,y,x);
    y-=a/b*x;
    return d;
}


int main()
{
    LL a,b;
    cin>>a>>b;
    LL x,y;
    exgcd(a,b,x,y);

    cout<<(x%b+b)%b<<endl;
    return 0;
}