I get -1080099800 when I run test case 99 99. And I also find my program will return a negative number of test case 40 56 in my own environment in spite of using long long.Who can tell me why?Here are my code.

```
#define maxn 105
int f[maxn][maxn];
int uniquePaths(int m, int n) {
if(f[m][n]) return f[m][n];
if(m == 1 && n == 1) return 1;
else if(m == 1) f[m][n] = uniquePaths(m, n - 1) ;
else if(n == 1) f[m][n] = uniquePaths(m - 1, n) ;
else f[m][n] = uniquePaths(m - 1, n) + uniquePaths(m, n - 1);
return f[m][n];
}
```