```cpp
#include<bits/stdc++.h>
using namespace std;
int main() {
long t, n, i;
char x[101], z[101];
cin >> n;
cin >> x;
cin >> z;
for (i = 0; i < n; i++) {
if (x[i] < z[i]) {
cout << -1 << endl;
return 0;
}
}
cout << z << endl;
return 0;
}
```
by zzz13548545966 @ 2023-01-29 16:17:53
#
------------
看看这个代码
by zzz13548545966 @ 2023-01-29 16:20:12