#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
#define rep(i,a,b) for(int i=a;i<b;i++)
#define repi(i,a,b) for(int i=a-1;i>=b;i--)
#define fi first
#define se second
#define MOD 100000007
#define ll long long
#define endl '\n'
#define fast ios_base::sync_with_stdio(false);cin.tie(nullptr);cout.tie(nullptr);
//#define int long long
using namespace std;
int n,x;
int32_t main(){
cin>>n;
cin>>x;
int a,b,c,ans=0;
rep(i,0,n){
cin>>a>>b;
if(abs(a-b)<=x){
ans+=max(a,b);
}
else{
cin>>c;
ans+=c;
}
}
cout<<ans;
}
