#include <fstream>
using namespace std;

#define MAX 1000000
#define hg 8192

int st,dr,mij,x,i,j,t,k,n,mat[8][380000],l[8],poz;
short v[MAX+1];
char ch[hg];

FILE *f=fopen("divprim.in","r");
FILE *g=fopen("divprim.out","w");

inline void cit (int &x) {
    x = 0;
    if (ch[0]=='\0') fread (ch, 1, hg, f);
    else while (ch[poz] < '0' || ch[poz] > '9')
            if (++poz == hg)
                fread (ch, 1, hg, f), poz = 0;

    while (ch[poz] >= '0' && ch[poz] <= '9') {
        x = x * 10 + ch[poz] - '0';
        if (++poz == hg)
            fread (ch, 1, hg, f), poz = 0;
    }
}
void citire() {
    cit(n);
    cit(k);
}
void ciur() {
    for(i=2; i<=MAX; i++)
        if(v[i]==0) {
            for(j=2*i; j<=MAX; j+=i)
                ++v[j];
            v[i]=1;
        }
    for (i=2; i<=MAX; i++)
        mat[v[i]][l[v[i]]++]=i;
}

int cb ( ) {
    int i, cnt;

    for (cnt = 1; cnt < l[k]; cnt <<= 1) ;
    for (i = 0; cnt; cnt >>= 1) {
        if (i + cnt < l[k] && mat[k][i + cnt] <= n) {
           i += cnt;
        }
    }

    return i;
}
    /*for (st=0, dr=l[k]-1, x=0; st <= dr ; ) {
        mij = st + ( (dr - st) >> 1 );
        if ( mat[k][mij] <= n )  st = mij + 1, x = mij;
        else if ( mat[k][mij] > n ) dr = mij-1;
    }
}*/
void afisare() {
    if (mat[k][0]>n)
        fprintf(g,"0\n");
    else {
        x = cb();
        if ( mat[k][x] <= n ) fprintf(g,"%d\n",mat[k][x]);
        else fprintf(g,"0\n");
    }
}
void final() {
    cit(t);
    while (t--) {
        citire();
        afisare();
    }
}
int main() {
    ciur();
    final();
    return 0;
}