*蓝桥OJ3904DNA序列配对

 

#include
using namespace std;

mapmp{
 	{'A',0},
	{'C',1},
	{'G',2},
	{'T',3}
};
	
int main()
{
	int n;cin >> n;
	string a, b;
	cin >> a >> b;
	int cnt = 0;
	for (int i = 0; i < n; i++)
	{
		if (mp[a[i]] + mp[b[i]] != 3)
			{
				for (int j = i +1 ; j  < n; j++)
					{
						if (mp[a[i]] + mp[b[j]] == 3 && mp[a[j]] + mp[b[i]] == 3)
						{
							swap(b[j],b[i]);
					    	break;	
						}  
					}
					cnt++;
			}
	}
	
	cout << cnt << '\n';
	return 0;
}