#include <stdio.h>
#include <string.h>
#define MAXN 100002
int dp[MAXN];
int main()
{
int i,j,n,m;
int cal[102],val[102];
while(scanf("%d",&n)!=EOF)
{
memset(dp,0,sizeof(dp));
for(i=0;i<n;++i)
scanf("%d %d",&val[i],&cal[i]);
scanf("%d",&m);
for(i=0;i<n;++i)
{
for(j=cal[i];j<=m;++j)
if(dp[j]<dp[j-cal[i]]+val[i])
dp[j]=dp[j-cal[i]]+val[i];
}
printf("%d\n",dp[m]);
}
return 0;
}