class Solution {
public:
    int uniquePaths(int m, int n) {
        vector<vector<int>> path(m, vector<int>(n));
        for (int i = 0; i < m; i++) path[i][0] = 1;
        for (int i = 0; i < n; i++) path[0][i] = 1;
        for (int i = 1; i < m; i++)
            for (int j = 1; j < n; j++)
                path[i][j] = path[i - 1][j] + path[i][j - 1];
        return path[m - 1][n - 1];
    }
};