#include<bits/stdc++.h>
using namespace std;
typedef unsigned long long ll;
ll a,b,c,d[10000000],e[10000000];
ll l=1,r=20000000000000000001,mid;
bool check(ll x)
{
	ll sum=0;
	for(int i=1;i<=a;i++)
	{
		if(d[i]+e[i]*x>=c)
		{
			sum+=d[i]+e[i]*x;			
		}	
		if(sum>=b) 
		{
			break;
		}
	}
	return sum>=b;	
}
int main(){	
	cin>>a>>b>>c;
	for(int i=1;i<=a;i++)
	{
		cin>>d[i];
	}	
	for(int i=1;i<=a;i++)
	{
		cin>>e[i];
	}	
	while(l<=r)
	{
		mid=(r+l)/2;
		if(check(mid))
		{
			r=mid-1;
		}
		else
		{
			l=mid+1;
		}
	}
	cout<<l<<endl;
	return 0;
}