#include<bits/stdc++.h>
using namespace std;
int n,a,i,s[1000005],l,ma,b;
const int f[13]={0,0,31,60,91,121,152,182,213,244,274,305,335};//预处理
void write(int x) {//快输
	if(x<0){
		putchar('-');
		write(-x);
		return;
	}
	if(x>=10)write(x/10);
	putchar(x%10+'0');
}
int main()
{
   cin>>n;
   for(i=1;i<=n;i++)cin>>a>>b,s[i]=f[a]+b;
   s[n+1]=366+1;//天数+1
   sort(s+1,s+n+1);//排序
   for(i=1;i<=n+1;i++)
      ma=max(ma,s[i]-s[i-1]-1);//跟间隔之间的天数取较大值
   write(ma*1.0*60*60*24/366+0.5);//转换
   return 0;
}