#include <stdio.h>int main(){    int t, a, b, i;    __int64 c;    scanf("%d", &t);    while(t--)    {        scanf("%d%d", &a, &b);        if(a < b)            printf("0\n");        else        {            c = 1;            for(i = 1; i <= b; i++)                c = c * (a - i + 1) / i;            printf("%I64d\n", c);        }    }    return 0;}