#include <fstream>
using namespace std;
ifstream fin("energii.in");
ofstream fout("energii.out");
int g[1001],v[1001],c[100001],n,S,i,j,INF;
int main()
{
    fin>>n>>S>>INF;
    for(i=1;i<=S;i++) c[i]=INF;
    for(i=1;i<=n;i++)
        for(j=S;j>=1;j--)
        {
            if(j<g[i]) c[j]=min(v[i],c[j]); else c[j] = min(c[j-g[i]]+v[i],c[j]);
        }
    if(c[S]==INF) fout<<"-1"; else fout<<c[S];
}
void read()
{
    fin>>n>>S;
    for(i=1;i<=n;i++) fin>>g[i]>>v[i];
}