/*
ID: samikgo1
TASK:
LANG: C++
*/
#include <bits/stdc++.h>
using namespace std;
typedef unsigned long long ll;
typedef pair<ll,ll> pii;
#define all(x) x.begin(),x.end()
#define allr(x) x.rbegin(),x.rend()
//#define f first
//#define s second
//#define x first
//#define y second
const int INF = INT32_MAX;
int main() {
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
// freopen("measurement.in","r",stdin);
// freopen("measurement.out","w",stdout);
int n,x;
cin >> n >> x;
int ans = 0;
for (int i = 0; i < n; i++) {
int a,b;
cin >> a >> b;
if(abs(a-b)<=x){
ans+=max(a,b);
} else {
int c;
cin >> c;
ans+=c;
}
}
cout << ans;
}
