//#include<iostream>
#include<fstream>

using namespace std;
ifstream cin("inversmodular.in");
ofstream cout("inversmodular.out");

using namespace std;
int cmmdc(int a, int b)
{
    if(b==0)return a;
    return cmmdc(b, a%b);
}

int inversModular(int a,int n){

    for(int i=1; ;i++){
        if(cmmdc(n*i+1,a)>1){return (n*i+1)/a;}

    }
}
main(){
int a,n;
cin>>a>>n;
cout<<inversModular(a,n);
}