#define DeBUG
#include <iostream>
#include <cstdio>
#include <cstring>
#include <cmath>
#include <cstdlib>
#include <algorithm>
#include <vector>
#include <stack>
#include <queue>
#include <string>
#include <set>
#include <sstream>
#include <map>
#include <bitset>
using namespace std ;
#define zero {0}
#define INF 2000000000
#define EPS 1e-6
typedef long long LL;
const double PI = acos(-1.0);
inline int sgn(double x){return fabs(x) < EPS ? 0 :(x < 0 ? -1 : 1);}
unsigned __int64 N(unsigned __int64 n)
{
if(n==0)
return 1;
return N(n-1)*n;
}
double C(int n,int m)
{
if(m>n)
return 0;
if(m<n/2.0)
m=n-m;
double s1=0;
for(int i=m+1;i<=n;i++)
{
s1+=log((double)i);
}
double s2=0;
int ub=n-m;
for(int i=2;i<=ub;i++)
{
s2+=log((double)i);
}
if(m>n)
return 0;
return exp(s1-s2);
}
int main()
{
#ifdef DeBUGs
freopen("C:\\Users\\Sky\\Desktop\\1.in","r",stdin);
#endif
int T;
scanf("%d", &T);
while(T--)
{
unsigned __int64 n,m;
cin>>n>>m;
if(m>n)
printf("0\n");
else
printf("%.0lf\n", C(n,m));
}
return 0;
}