#include<bits/stdc++.h>
using namespace std;
const int maxh=50005;
const int inf=0x3f3f3f3f;
int n,h;
int p[111],c[111];
int dp[maxh];
int main(){
cin>>n>>h;
for(int i=1;i<=n;i++)cin>>p[i]>>c[i];
memset(dp,0x3f,sizeof(dp));
dp[0]=0;
for(int i=1;i<=n;i++)for(int j=1;j<=h;j++){
int f=max(0,j-p[i]);
dp[j]=min(dp[j],dp[f]+c[i]);
}cout<<dp[h]<<endl;
}