Unique path - bottom up DP

int uniquePaths(int m, int n){
    int M[m][n];

    for (int i = 0; i < m; i++)
        M[i][0] = 1;

    for (int j = 0; j < n; j++)
        M[0][j] = 1;

    for (int i = 1; i < m; i++)
        for(int j = 1; j < n; j++)
            M[i][j] = M[i-1][j] + M[i][j-1];

    return M[m-1][n-1];
}