public class Solution {    public int uniquePaths(int m, int n) {        int [][] result = new int[m][n];        for (int i=0; i<m; i++) {            for (int j=0; j<n; j++) {                if (i==0 || j==0) result[i][j] = 1;                else result[i][j] = result[i][j-1] + result[i-1][j];            }        }                return result[m-1][n-1];    }}