1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
#include<bits/stdc++.h>
#include "message.h"
#include "futbol.h"
using namespace std;

long long int n,k,p,i,w,h,f[10000007];
long long int pow(long long int base, long long int exp)
{
	long long int res=1;
	while(exp > 0)
	{
		if(exp%2 == 1)
		{
			res*=base;
			res%=p;
		}
		base*=base;
		base%=p;
		exp/=2;
	}
	return res;
}
int main()
{
	if(MyNodeId() > 0)
	{
		return 0;
	}
	f[0]=1;
//	scanf("%lld%lld%lld", &n, &k, &p);
	n=GetN();
	k=GetK();
	p=GetP();
	for(i=1; i<=n; i++)
	{
		f[i]=f[i-1]*i;
		f[i]%=p;
//		printf("TEST factorial[%lld]=%lld;\n", i, f[i]);
	}
	for(i=0; i<=k; i++)
	{
		h=f[n];
		h*=pow((f[i]*f[n-i])%p, p-2);
		w+=h;
		w%=p;
	}
	printf("%lld", w);
	return 0;
}