#include <queue>
#include <vector>
#include <iostream>

typedef std::vector<std::vector<unsigned int>> Matrix;

struct Cell {
    unsigned int x;
    unsigned int y;
    unsigned long long weight;

    Cell(unsigned int x_, unsigned int y_, unsigned long long weight_) : x(x_), y(y_), weight(weight_) {}

    bool operator<(const Cell& cell) const {
        return weight > cell.weight;
    }
};

unsigned long long search(const Matrix& matrix) {
    const auto size = matrix.size();
    std::vector<std::vector<bool>> processed(matrix.size());
    for(auto& row : processed) {
        row.resize(size, false);
    }
    std::priority_queue<Cell> next;
    next.push(Cell(0, 0, matrix[0][0]));
    while(!next.empty()) {
        Cell cell = next.top();
        next.pop();
        if(!processed[cell.y][cell.x]) {
            processed[cell.y][cell.x] = true;
            if(cell.x == size - 1 && cell.y == size - 1) {
                return cell.weight;
            }
            if(cell.x + 1 < size) {
                next.push(Cell(cell.x + 1, cell.y, cell.weight + matrix[cell.y][cell.x + 1]));
            }
            if(cell.y + 1 < size) {
                next.push(Cell(cell.x, cell.y + 1, cell.weight + matrix[cell.y + 1][cell.x]));
            }
            if(cell.y > 0) {
                next.push(Cell(cell.x, cell.y - 1, cell.weight + matrix[cell.y - 1][cell.x]));
            }
            if(cell.x > 0) {
                next.push(Cell(cell.x - 1, cell.y, cell.weight + matrix[cell.y][cell.x - 1]));
            }
        }
    }
    return -1;
}

int main() {
    unsigned int N;
    std::cin >> N;

    Matrix matrix(N);
    for(auto& row : matrix) {
        row.resize(N);
        for(auto& cell : row) {
            std::cin >> cell;
        }
    }
    std::cout << search(matrix) << std::endl;
    return 0;
}