#include "bits/stdc++.h"
#define rep(i, a, n) for (auto i = a; i <= (n); ++i)
#define revrep(i, a, n) for (auto i = n; i >= (a); --i)
#define all(a) a.begin(), a.end()
#define sz(a) (int)(a).size()

using namespace std;
using ll = long long;
using pii = pair<int, int>;
using vi = vector<int>;
using vvi = vector<vi>;

int main() {
	ios::sync_with_stdio(0); cin.tie(0);

	string s, t; cin >> s >> t;
	int n = sz(s);
	vvi nxt(n + 1, vi(26, n));
	ll ans = 0;
	revrep(i, 0, n - 1) {
		nxt[i] = nxt[i + 1];
		int c = s[i] - 'a';
		nxt[i][c] = i;
		int now = i;
		for (auto ch: t) {
			int c = ch - 'a';
			if (now >= n) {
				now = n + 1;
				break;
			}
			now = nxt[now][c] + 1;
		}
		if (now <= n) ans += n - now + 1;
	}
	printf("%lld\n", ans);
	return 0;
}