#include<bits/stdc++.h>
        
using namespace std;

int n, x;     
long long ans = 0;
int a[10005];
        
int main()
{
    freopen("running.in", "r", stdin);
   	freopen("running.out", "w", stdout);
           	
    ios::sync_with_stdio(false);
   	cin.tie(0); cout.tie(0);
        	
    cin >> n >> x; 
    for (int i = 1; i <= n; ++i)
        cin >> a[i];
    for (int i = 1; i <= n; ++i)
    {
        int b;
        cin >> b;
        ans += (a[i]-b)*x;
        if(ans > 10000)
        {
            cout << "2 hard 4 me";
            return 0;
        }
    }
    
    cout << ans;
        	
   	return 0;
}