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