1 #include<stdio.h>
2 #include<string.h>
3 int a[100005][11];
4 int main()
5 {
6 int n,i,j,t,time;
7 while(~scanf("%d",&n)&&n)
8 {
9 time=0;
10 memset(a,0,sizeof a);
11 while(n--)
12 {
13 scanf("%d%d",&i,&j);
14 if(j>time)
15 time=j;
16 a[j][i]++;
17 }
18 for(i=time-1; i>0; --i)
19 for(j=0; j<11; ++j)
20 {
21 if(j==0)
22 a[i][j] += a[i+1][j]>a[i+1][j+1]?a[i+1][j]:a[i+1][j+1];
23 else if(j==10)
24 a[i][j] += a[i+1][j]>a[i+1][j-1]?a[i+1][j]:a[i+1][j-1];
25 else
26 {
27 t = a[i+1][j] > a[i+1][j+1] ? a[i+1][j] : a[i+1][j+1];
28 a[i][j] += a[i+1][j-1] > t ? a[i+1][j-1] : t;
29 }
30 }
31 t=a[1][4]>a[1][5]?a[1][4]:a[1][5];
32 t=a[1][6]>t?a[1][6]:t;
33 printf("%d\n",t);
34 }
35 }
