#include<stdio.h>
long long cmmdc(long long a,long long b){
    long long r;
    while(b!=0){
        r=a%b;
        a=b;
        b=r;
    }
    return a;
}
int main(){
    long long a,i,r,b;
    freopen("frac.in","r",stdin);
    freopen("frac.out","w",stdout);
    scanf("%lld%lld",&a,&b);
    r=0;
    if(cmmdc(a,2)==1)
        r=1;
    i=1;
    while(r<b){
        i+=2;
        if(cmmdc(a,i)==1)
            r++;
    }
    printf("%lld",i-2);
    return 0;
}