#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;

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

int main(){
	Solution mysolution;
	cout << mysolution.uniquePaths(2,1);
	return 0; 
}