// I wasn't going to get a brain transplant,
// but then I changed my mind
#include<bits/stdc++.h>
using namespace std;
#define _ ios_base::sync_with_stdio(0);cin.tie(0);
#define pb emplace_back
#define mp make_pair
#define F first
#define S second
#define repp(i, x, y) for (__typeof(x) i = x; i < y; i++)
#define rep(i, x) repp(i, 0, x)
#define all(a) (a).begin(),(a).end()
#define endl '\n'
#define DB(x) cerr << #x << " is " << x << endl;
#define TEST(T) int T; cin >> T; rep(_i, T)
#define MOD 1000000007
#define int long long
typedef vector<int> vi;
typedef pair<int, int> pii;
typedef vector<pii> vii;
typedef set<int> si;
#define MAX 200000
string a, b;
bitset<MAX> bi;
int isSub(){
int i= 0, j = 0;
int p = a.size(), q = b.size();
bi.reset();
for(;i<p && j<q; i++){
if (a[i] == b[j]) bi[i] = 1, j++;
}
return j == q;
}
int32_t main(){ _
cin >> a >> b;
int t;
bi.set();
rep(i, a.size()){
cin >> t; t--;
a[t] = '$';
if (bi[t]){
if (!isSub()){
cout << i; return 0;
}
}
}
}
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