#include <string>
#include <vector>

using namespace std;

int solution(vector<vector<int>> board, int k) {
    int answer = 0;
    
    for (int i=0; i<board.size(); i++)
    {
        for (int j=0; j<board[i].size(); j++)
        {
            if (i+j <= k)
            {
                answer += board[i][j];
            }
        }   
    }
    
    return answer;
}