class Solution {

public:

    int num[110][110];

    int dfs(int m,int n,int x,int y)

    {

        if(num[x][y]) return num[x][y];

        if(x==m-1 && y==n-1) return 1;

        if(x+1<m) num[x][y]+=dfs(m,n,x+1,y);

        if(y+1<n) num[x][y]+=dfs(m,n,x,y+1);

        return num[x][y];

    }

    int uniquePaths(int m, int n) {

        memset(num,0,sizeof(num));

        return dfs(m,n,0,0);

    }

};