test·A·Summary

#include<cstdio>
#include<iostream>
#include<cmath>
#include<algorithm>
#include<cstring>
using namespace std;
void read(int& x)
{
	x = 0;
	char c = getchar();
	bool flag = 0;
	while(c<'0'||c>'9')
	{
		if(c=='-')flag=1;
		c = getchar();
	}
	while(c>='0'&&c<='9')
	{
		x = x*10+c-'0';
		c =getchar();
	}
	if(flag)x = -x;
}
#define maxn 1001000
#define eps 0.000001
typedef long long ll;
double ans = 0.0;
int n,p;
int a[maxn];
int pre[maxn],suf[maxn];
double tmp;
int main()
{
#define AC
#ifdef AC
	freopen("nsq.in","r",stdin);
	freopen("nsq.out","w",stdout);
#endif
	read(n),read(p);
	for(int i=1;i<=n;i++)read(a[i]);
	pre[0] = 1,suf[n+1]=1;
	for(int i=1;i<=n;i++)pre[i] = (ll)pre[i-1]*a[i]%p;
	for(int i=n;i