题解

#include<bits/stdc++.h>
#define ms(i,j) memset(i,j,sizeof i);
using namespace std;
struct node{
	int p,t;
}s[2005];
bool cmp(const node &a,const node &b){
	if(a.t == b.t){
		return a.p < b.p;
	}else{
		return a.t < b.t;
	} 
}
int n;
int a[10];
int ans = 0;
int main(){
	cin >> n;
	for(int i = 1;i <= n;i++){
		cin >> s[i].p >> s[i].t;
	}
	sort(s + 1,s + 1 + n,cmp);
	ms(a,0);
	for (int i = 1;i <= n;i++){
		if(a[s[i].p] == 0){
			a[s[i].p] = i;
			ans++;
		} 
		if(s[i].t - s[a[s[i].p]].t >= 60){
			ans++;
			a[s[i].p] = i;
		}
	}
	cout << ans;
	return 0;
}