#include <iostream>
#include <vector>
using namespace std;

int main()
{
   int n;
   cin >> n;

    vector<int> v(100000, 0);
   for(int i = 0; i < n; i++) {
    string S, E;
    cin >> S >> E;

    int h = (S[0] - '0') * 10 + (S[1] - '0');
    int m = (S[3] - '0') * 10 + (S[4] - '0');
    int s = (S[6] - '0') * 10 + (S[7] - '0');

    int t = h * 3600 + m * 60 + s;

    v[t]++;

    h = (E[0] - '0') * 10 + (E[1] - '0');
    m = (E[3] - '0') * 10 + (E[4] - '0');
    s = (E[6] - '0') * 10 + (E[7] - '0');

    t = h * 3600 + m * 60 + s;
    v[t + 1]--;
   }

   int sum = 0;
   int res = 0;
   for(int i = 0; i < 100000; i++) {
      sum += v[i];
      res = max(res, sum);
   }
  cout << res << endl;
    return 0;
}