Description：

Solution：

Code：

#include<algorithm>

#include<iostream>

#include<cstdlib>

#include<cstdio>

#include<cmath>

#include<cctype>

#include<cstring>

using namespace std;

inline int rd()

{

	register int res = 0,f = 1;register char c = getchar();

	while(!isdigit(c)){if(c == '-')f = -1;c = getchar();}

	while(isdigit(c))res = (res << 1) + (res << 3) + c - '0',c = getchar();

	return res * f;

}

int n;

#define MAXN 400010

int c[MAXN];

typedef long long ll;

ll x[MAXN],y[MAXN];

struct state

{

	int val,tp;

}s[MAXN];

bool operator == (state a,state b){return (a.val == b.val && a.tp == b.tp);}

ll dis(int a,int b){return (x[a] - x[b]) * (x[a] - x[b]) + (y[a] - y[b]) * (y[a] - y[b]);}

ll cross(int a,int b,int c){return (x[b] - x[a]) * (y[c] - y[b]) - (y[b] - y[a]) * (x[c] - x[b]);}

int h[MAXN];

void work()

{

	scanf("%d",&n);

	for(int i = 1;i <= n;++i)scanf("%d%d",&x[i],&y[i]);

	int tot = 0;

	for(int i = 1;i <= n;++i)

	{

		int nxt = i % n + 1,nxtt = (i + 1) % n + 1;

		s[++tot] = (state){dis(i,nxt),1};

		s[++tot] = (state){cross(i,nxt,nxtt),2};

	}

	for(int i = 2 * n + 1;i <= 4 * n;++i)s[i] = s[i - 2 * n];

	tot = 4 * n - 1;

	int maxr = 0,pos;

	int ans = 0;

	for(int i = 1;i <= tot;++i)

	{

		if(maxr > i)h[i] = min(h[2 * pos - i],maxr - i + 1);

		else h[i] = 1;

		while(i - h[i] >= 1 && i + h[i] <= 4 * n && s[i - h[i]] == s[i + h[i]])++h[i];

		if(i + h[i] - 1 > maxr)

		{

			maxr = i + h[i] - 1;

			pos = i;

		}

		ans += (h[i] >= n);

	}

	cout << ans / 2 << endl;

	return;

}

int main()

{

	int testcases = rd();

	while(testcases--)work();

	return 0;

}