#include <bits/stdc++.h>
using namespace std;
int n,x,z;
int a[1010];

inline int read(){
	int t=0,f=1;
	register char c=getchar();
	while(c<'0'||c>'9') f=(c=='-')?(-1):(f),c=getchar();
	while(c>='0'&&c<='9') t=(t<<3)+(t<<1)+(c^48),c=getchar();
	return t*f;
}

int main(){
	freopen("running.in","r",stdin);
	freopen("running.out","w",stdout);
	n=read(),x=read();
	for(int i=1;i<=n;i++) a[i]=read();
	for(int i=1;i<=n;i++){
		int f=read();
		z+=(a[i]-f)*x;
		if(z>10000){
			printf("2 hard 4 me\n");
			return 0;
		}
	}
	printf("%d",z);
	return 0;
}