///https://www.instagram.com/_modwwe/
#include<bits/stdc++.h>
#define int long long
//#define ll long long
#define down cout<<'\n';
#define NHP ios_base::sync_with_stdio(0);cout.tie(0);cin.tie(0);
#define modwwe int t;cin>>t; while(t--)
#define bit(i,j) (i>>j&1)
#define sobit(a) __builtin_popcountll(a)
#define task "test"
#define fin(x) freopen(x".inp","r",stdin)
#define fou(x) freopen(x".out","w",stdout)
#define pb push_back
#define checktime cerr << (double)clock() / CLOCKS_PER_SEC * 1000 << " ms";
using namespace std;
void phongbeo();
const int inf=1e18;
const int mod2=1e9+7;
const int mod1=998244353;
struct icd
{
int a,b;
};
struct ib
{
int a;
int b;
};
struct ic
{
int a,b,c;
};
struct id
{
int a,b,c,d;
};
struct ie
{
int a,b,c, d,e,f;
};
int n,m,s1,s2,s4,s3,sf,k,r,mid,s5,s6,mx,s7,s8,s9,mx2,res,dem2=0,dem=0,l;
int i,s10,s12;
int el=29;
main()
{
#ifndef ONLINE_JUDGE
// fin(task),fou(task);
#endif
NHP
/// cin>>s1;
// modwwe
phongbeo();
}
int dp[100001];
int b[301];
void solve1()
{
for(int i=1;i<=m;i++){
for(int j=s4-b[i];j>=0;--j)
if(dp[j]!=inf)
dp[j+b[i]]=max(dp[j+b[i]],dp[j]+min(b[i],n));
}
s3=inf;
for(int j=s2;j<=s4;j++)
if(dp[j]>=n*k)
s3=min(s3,j-s2);
}
void phongbeo()
{
cin>>n>>m>>k;
s7=inf;
for(int i=1;i<=n;i++)cin>>l,s2+=l,s7=min(s7,l);
for(int i=1;i<=m;i++) cin>>b[i],s4+=b[i];
for(int i=0;i<=s4;i++)
dp[i]=-1e18;
if(s7<k){cout<<"Impossible";exit(0);}
dp[0]=0;
solve1();
if(s3!=inf) cout<<s3;
else cout<<"Impossible";
}
