```
class Solution(object):
def uniquePaths(self, m, n):
"""
:type m: int
:type n: int
:rtype: int
"""
dp = [[0 for j in range(n+1)] for i in range(m+1)]
for i in range(1, m+1):
for j in range(1, n+1):
if i == j == 1:
dp[i][j] = 1
else:
dp[i][j] = dp[i-1][j] + dp[i][j-1]
return dp[m][n]
```