#include <bits/stdc++.h>
using namespace std;
int main()
{
map<int, int> S;
int n, res = 0;
scanf("%d", &n);
for (int i = 0; i < n; i ++ )
{
int h, m;
scanf("%d%d", &h, &m);
res = max(res, ++ S[h * 60 + m]);
}
printf("%d", res);
return 0;
}