#include<iostream>
#include<cstring>
#include<cstdio>
#include<algorithm>
#include<vector>
#define maxn 1000005
using namespace std;
vector<int>in[maxn];
vector<int>out[maxn];
namespace solution{long long ANS=0;inline void read(int &x){x=0;int f=1;char ch=getchar();while(ch<'0'||ch>'9'){if(ch=='-')f=-1;ch=getchar();}while(ch>='0'&&ch<='9'){x=x*10+ch-'0';ch=getchar();}x*=f;}int N,K,M,n;struct node{long long l,r;long long sum;long long add;}tree[maxn<<2];inline void push_up(int rt){tree[rt].add=tree[rt<<1].add+tree[rt<<1|1].add;tree[rt].sum=tree[rt<<1].sum+tree[rt<<1|1].sum;}void build(int rt,int l,int r){tree[rt].l=l;tree[rt].r=r;if(l==r)return ;long long mid=l+r>>1;build(rt<<1,l,mid);build(rt<<1|1,mid+1,r);}void update(int rt,int p,long long x){//cout<<"update note: "<<tree[rt].l<<" "<<tree[rt].r<<" "<<p<<" "<<x<<endl; if(tree[rt].l==tree[rt].r){tree[rt].sum+=x;tree[rt].add+=x*p;return ;}int mid=tree[rt].l+tree[rt].r>>1;if(p<=mid)update(rt<<1,p,x);elseupdate(rt<<1|1,p,x);push_up(rt);}long long query(int rt,int l,int r){//cout<<"query note: "<<tree[rt].l<<" "<<tree[rt].r<<" "<<l<<" "<<r<<endl;if(l<=tree[rt].l&&tree[rt].r<=r)return tree[rt].sum;int mid=tree[rt].l+tree[rt].r>>1;long long ans=0;if(l<=mid)ans+=query(rt<<1,l,r);if(r>mid)ans+=query(rt<<1|1,l,r);return ans;}long long query_add(int rt,int l,int r){//    cout<<"query note: "<<tree[rt].l<<" "<<tree[rt].r<<" "<<tree[rt].add<<endl;if(l<=tree[rt].l&&tree[rt].r<=r)return tree[rt].add;int mid=tree[rt].l+tree[rt].r>>1;long long ans=0;if(l<=mid)ans+=query_add(rt<<1,l,r);if(r>mid)ans+=query_add(rt<<1|1,l,r);return ans;}struct plan{int l,r,p,c;friend bool operator < (plan a,plan b){return a.l<b.l;}}plan[maxn];void getin(){read(N);read(K);read(M);for(int i=1;i<=M;i++){read(plan[i].l);read(plan[i].r);read(plan[i].c);read(plan[i].p);n=max(n,plan[i].p);in[plan[i].l].push_back(i);out[plan[i].r+1].push_back(i);}}long long find(int rt,int k){//    cout<<"find note: "<<tree[rt].l<<" "<<tree[rt].r<<" "<<tree[rt<<1].sum<<endl; if(tree[rt].l==tree[rt].r)return tree[rt].l;int mid=tree[rt].l+tree[rt].r>>1;if(tree[rt<<1].sum>=k)return find(rt<<1,k);elsereturn find(rt<<1|1,k-tree[rt<<1].sum);/*int l=1,r=n,mid,ans=n;while(l<=r){mid=l+r>>1;//cout<<"find note: "<<l<<" "<<r<<" "<<mid<<" "<<query(1,1,mid)<<endl; if(query(1,1,mid)>=K)r=mid-1,ans=mid;elsel=mid+1;}return ans;*/}void work(){for(int i=1;i<=N;i++){for(vector<int>::iterator it=in[i].begin();it!=in[i].end();it++)  {int top=*it;//cout<<"in note: "<<top<<" "<<plan[top].p<<" "<<plan[top].c<<" ";update(1,plan[top].p,plan[top].c);//cout<<query(1,1,plan[top].p)<<endl;
            }for(vector<int>::iterator it=out[i].begin();it!=out[i].end();it++){int top=*it;//cout<<"out note:"<<top<<endl;update(1,plan[top].p,plan[top].c*-1);}long long tot=query(1,1,n);int f=0;if(tot<=K)ANS+=query_add(1,1,n);else{f=find(1,K);long long d=query_add(1,1,f)-(query(1,1,f)-K)*f;//    cout<<"NOTE: "<<query_add(1,1,f)<<" "<<query(1,1,f)<<endl;ANS+=d;}//cout<<"day:"<<i<<" "<<f<<" "<<ANS<<endl;
        }}void put_out(){printf("%lld",ANS);}void solve(){getin();build(1,1,n);work();put_out();}
}
int main()
{solution::solve();
}