class Solution {
public:
    int minimumTotal(vector<vector<int>>& tr) {
        int n = tr.size();
        vector<vector<int>> f(n+1, vector<int>(n+1));

        for(int i = n-1; i >= 0; i--) 
            for(int j = 0; j <= i; j++)
                f[i][j] = min(f[i+1][j], f[i+1][j+1]) + tr[i][j];
        return f[0][0];
    }
};