#include<bits/stdc++.h>
using namespace std;
int n,cnt=1,t,last,a,b,k=0;
char c;
int main() {
	cin>>n;
	getchar();
	while(n--) {
		scanf("[%d:%d %1c",&a,&b,&c);
		while(getchar()!='\n');
		a%=12;
		if(c=='p')a+=12;
		t=a*60+b;
		if(t<last)++cnt;
		if(t==last)++k;
		else k=1;
		if(k>10)++cnt,k=1;
		last=t;
	}
	cout<<cnt;
	return 0;
}