#include <iostream>
#include <fstream>
#include <vector>
#include <stack>
#include <algorithm>

using namespace std;

int main()
{
    //std::ifstream in("input.txt");
    //std::cin.rdbuf(in.rdbuf());

    //std::ofstream out("output.txt");
    //std::cout.rdbuf(out.rdbuf());

    int n;
    cin >> n;

    vector< vector<int> > adjacentMatrix(n, vector<int>(n));
    int edges = 0;
    int edge;

    for(int i = 0; i < n; ++i)
    {
        for(int j = 0; j < n; ++j)
        {
            cin >> edge;
            edges += adjacentMatrix[i][j] = edge;
        }
    }
    edges /= 2;

    stack<int> stack;
    vector<bool> isVisited(n);
    int visitedCount = 1;
    int u;

    stack.push(0);
    while(!stack.empty())
    {
        u = stack.top();
        stack.pop();

        for(int v = 0; v < n; ++v)
            if(adjacentMatrix[u][v] && !isVisited[v])
            {
                stack.push(v);
                isVisited[u] = true;
                ++visitedCount;
            }
    }

    if(edges == (n - 1) && visitedCount == n)
        cout << "Yes\n";
    else
        cout << "No\n";

    return 0;
}