求调

#include <bits/stdc++.h>

using namespace std;

const int N=1e3+10;
const int H=1e3;
bool val[H][N];
int res;
int main(){
    int n;
    cin >> n;
    int l=60;
    while(n--){
        int a,b;
        cin >> a >> b;
        if(l-b<=0){
            res++;
            l=60;
            for(int i=1;i<=60;i++) val[a][i]=0;
        }
        val[a][l-b%60]=1;
        l-=b%60;
    }
    cout << res;
}