#include<bits/stdc++.h>
#define inl inline
using namespace std;
const int N=1005,IB=1<<21; char IN[IB],*IS=IN+IB,*IT=IS;
#define getchar() (IS==IT&&(IT=IN+fread(IS=IN,1,IB,stdin)),IS==IT?EOF:*IS++)
struct A {int c,v; }a[N];
int n,an,b[N],f[N][N];
inl int Read()
{
	int s=0; char c; while(!isdigit(c=getchar()));
	for(;isdigit(c);c=getchar()) s=s*10+c-'0'; return s;
}
int main()
{
	n=Read(); for(int i=1;i<=n;++i) a[i]={Read(),Read()}, ++b[a[i].c];
	sort(a+1,a+n+1,[](A x,A y){return x.c==y.c?x.v>y.v:x.c<y.c; });
	memset(f,63,sizeof(f)); for(int i=1;i<=n;++i) b[i]+=b[i-1];
	an=f[0][0]; f[n+1][0]=0; for(int i=n;i;--i)
	{
		for(int j=a[i].c-b[a[i].c-1];j<=n-i;++j) f[i][j]=f[i+1][j];
		for(int j=0;j<=n-i;++j) f[i][j+1]=min(f[i][j+1],f[i+1][j]+a[i].v);
for(int j=1;j<=n;++j) if(f[i][j-1]!=an) assert(f[i][j-1]<=f[i][j]);
	}
	for(int i=0;i<=n;++i) an=min(an,f[1][i]);
	printf("%d\n",an); return 0;
}