#include<bits/stdc++.h>
using namespace std;
int main()
{
	freopen("heaven.in","r",stdin);
	freopen("heaven.out","w",stdout);
	int n,D[13][32]={0},M[13]={0,31,60,91,121,152,182,213,244,274,305,335,366};
	double ans=0;
	cin>>n;
	if(n==366)
	{
		cout<<0;
		return 0;
	}
	for(int i=1;i<=n;i++)
	{
		int a,b;
		cin>>a>>b;
		D[a][b]=1;
	}
	int m=1,awa[n],x=0;
	for(int i=1;i<=366;i++)
	{
		for(int j=m;j<=12;j++)if(M[j]>i){m=j;break;}
		if(D[m][i-M[m-1]]==1)
		{
			if(ans<i-x&&x!=0)ans=i-x;
			x=i;
		}
	}
	ans--;
	double ansa;
	ansa=ans/366*24*3600;
	printf("%.0lf",ansa);
	return 0;
}