itsa58 5Set partition

#include<iostream>
#include<string>
#include<sstream>
#include<iomanip>
using namespace std;
void replaceD(string &str)
{
int i = 0;
while(i < str.length())
{
if (str[i] == ',')
str[i] = ' ';
i++;
}
}
long double F(int m,int n)
{
if (n == 1|| m == n)
return 1;
else if (n == 0)
return 0;
return F(m - 1,n - 1) + n * F(m - 1,n);
}
int main()
{
int N,m,n;
long long sum = 0;
string str;
cin >> N;
getline(cin,str);
for (int i = 0;i < N; i++)
{
getline(cin,str);
replaceD(str);
stringstream ss(str);
ss >> m >> n;
sum = F(m,n);
cout << fixed << setprecision(0) << sum << endl;
}
return 0;
}