#include<stdio.h>
#include<math.h>
int main()
{long unsigned n,p,k,j,i,r,a,b,nr;
FILE *f,*g;
f=fopen("frac.in","r");
g=fopen("frac.out","w");
fscanf(f,"%ld %ld",&n,&p);
k=0;
if(n%2==0) {j=2;i=1;}
else {j=1;i=1;}
while (k<p)
			 {a=i;
				b=n;
			  r=a%b;
			  while (r!=0) {a=b; b=r; r=a%b;}
					  if (b==1){nr=i;k++; }
		 		  i=i+j;}
fprintf(g,"%ld",nr);
fclose(f);
fclose(g);
return 0;}