Description：

Solution：

Code：

#include<algorithm>

#include<iostream>

#include<cstdlib>

#include<cstdio>

#include<cmath>

#include<stack>

#include<queue>

#include<bitset>

#include<vector>

#include<cstring>

using namespace std;

int getbit()

{

	register char c = getchar();

	while(!isdigit(c))c = getchar();

	return c - '0';

}

int n;

#define MAXN 2010

struct edge

{

	int to,nxt;

}e[MAXN * MAXN];

int edgenum = 0;

int lin[MAXN] = {0};

void add(int a,int b)

{

	++edgenum;e[edgenum].to = b;e[edgenum].nxt = lin[a];lin[a] = edgenum;

	return;

}

stack<int> s;

int dfn[MAXN],low[MAXN],tot = 0;

bool v[MAXN];

int scc = 0,ins[MAXN],siz[MAXN];

bitset<MAXN> f[MAXN];

void tarjan(int k)

{

	dfn[k] = low[k] = ++tot;

	s.push(k);v[k] = true;

	for(int i = lin[k];i != 0;i = e[i].nxt)

	{

		if(dfn[e[i].to] == 0)

		{

			tarjan(e[i].to);

			low[k] = min(low[k],low[e[i].to]);

		}

		else if(v[e[i].to])

		{

			low[k] = min(low[k],dfn[e[i].to]);

		}

	}

	if(dfn[k] == low[k])

	{

		int t;

		++scc;siz[scc] = 0;

		do

		{

			t = s.top();s.pop();

			ins[t] = scc;v[t] = false;

			++siz[scc];f[scc][t] = true;

		}while(t != k);

	}

	return;

}

vector<int> g[MAXN];

int ind[MAXN];

int main()

{

	scanf("%d",&n);

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

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

			if(getbit())add(i,j);

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

		if(dfn[i] == 0)tarjan(i);

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

	{

		for(int i = lin[k];i != 0;i = e[i].nxt)

		{

			if(ins[k] != ins[e[i].to])

			{

				g[ins[e[i].to]].push_back(ins[k]);

				++ind[ins[k]];

			}

		}

	}

	int ans = 0;

	queue<int> q;

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

	{

		q.push(i);

	}

	while(!q.empty())

	{

		int k = q.front();q.pop();

		for(vector<int>::iterator i = g[k].begin();i != g[k].end();++i)

		{

			f[*i] |= f[k];

			--ind[*i];

			if(ind[*i] == 0)

			{

				q.push(*i);

			}

		}

	}

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

	{

		ans += siz[i] * (f[i].count() - siz[i]) + siz[i] * siz[i];

	}

	cout << ans << endl;

	return 0;

}