using namespace std; 
#define nmax 1002 
#define inf 32000 
#define wmax 15002 
#include<cstdio> 
long  v[nmax],c[nmax],n,j,cmin[15003],w,i; 
void read() 
{freopen("energii.in","r",stdin); 
 scanf("%li%li",&n,&w);  
 for(i=1;i<=n;i++) scanf("%li%li",&v[i],&c[i]); 
} 
void solve() 
{for(i=1;i<=wmax;i++) cmin[i]=inf; 
for(j=1;j<=n;j++) for(i=w-1;i>=0;i--) if(cmin[i+v[j]]> min[i]+c[j]) cmin[i+v[j]]=cmin[i]+c[j]; 
}
void afis() 
{long min=inf; 
 freopen("energii.out","w",stdout); 
 for(i=w;i<=wmax;i++) if(cmin[i]<min) min=cmin[i]; 
 printf("%li\n",min); 
} 
int main() 
{read(); 
 solve(); 
 afis(); 
return 0; 
}