#include<bits/stdc++.h>
using namespace std;
int main()
{
	int n,h,g=0,x1,x2;cin>>n>>h;
	for(int i=1;i<=n;i++)
	{
		cin>>x1>>x2;
		if(x1<=h)g+=x2;
	}
	cout<<g;
	return 0;
}