#include <bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < n; ++i)
using ll = long long;
using namespace std;
const int INF = 1e9;

int main() {
    string s, t;
    cin >> s >> t;

    bool flag = true;
    if (strncmp(&s[0], &t[0], s.size()) != 0)
        flag = false;

    if (flag && t[t.size() - 1] == '0')
        cout << "Yes";
    else
        cout << "No";
    cout << endl;

    return 0;
}