#include <iostream>
#include <vector>
#include <algorithm>
#include <iterator>
#include <unordered_map>
#include <functional>
#include <unordered_set>
#include <string>
#include <set>
#include <utility>
#include <stack>
#include <limits.h>

std::vector<std::vector<long long>> matrix;

int main() {
    long long N, a;
    std::cin >> N;
    std::vector<long long> line;
    for (int i = 0; i < N; i++) {
        for (int j = 0; j < N; j++) {
            std::cin >> a;
            if (a == 0) {
                line.push_back(LLONG_MAX);
            } else {
                line.push_back(a);
            }
        }
        matrix.push_back(line);
        line.clear();
    }
    long long result = 0;
    for (int n = 0; n < N; n++) {
        for (int i = 0; i < N; i++) {
            for (int j = 0; j < N; j++) {
                if (i != j) {
                    if (matrix[i][n] != LLONG_MAX &&
                        matrix[n][j] != LLONG_MAX) {
                        matrix[i][j] = std::min(matrix[i][j],
                            matrix[i][n] + matrix[n][j]);
                    }
                }
            }
        }
    }
    for (int i = 0; i < N; i++) {
        for (int j = 0; j < N; j++) {
            if (matrix[i][j] != LLONG_MAX && matrix[i][j] > result) {
                result = matrix[i][j];
            }
        }
    }
    std::cout << result;
}