参考答案：

#include <iostream>
#include <map>
using namespace std;
map<string, int>p;
int main()
{
    int n;
    scanf("%d", &n);
    string s;
    for (int i = 1; i <= n; i++)
    {
        cin >> s;
        p[s]++;
    }
    cout << p.size() << endl;
    return 0;
}