#include <bits/stdc++.h>
using namespace std;
template <class T>
inline void umax(T &a, T b) {
  if (a < b) a = b;
}
template <class T>
inline void umin(T &a, T b) {
  if (a > b) a = b;
}
template <class T>
inline T abs(T a) {
  return a > 0 ? a : -a;
}
template <class T>
inline T gcd(T a, T b) {
  return __gcd(a, b);
}
template <class T>
inline T lcm(T a, T b) {
  return a / gcd(a, b) * b;
}
long long modpow(long long a, long long n, long long temp) {
  long long res = 1, y = a;
  while (n > 0) {
    if (n & 1) res = (res * y) % temp;
    y = (y * y) % temp;
    n /= 2;
  }
  return res % temp;
}
long long getbit(long long j, long long i) { return ((i >> (j - 1ll)) & 1ll); }
long long ison(long long mask, long long pos) { return (mask & (1 << pos)); }
long long cbit(long long n) {
  long long k = 0;
  while (n) n &= (n - 1), k++;
  return k;
}
long long nbit(long long n) {
  long long k = 0;
  while (n) n /= 2, k++;
  return k;
}
long long mod = 1e9 + 7;
int sgn(long long x) { return x < 0 ? -1 : !!x; }
const double eps = 1e-7;
const double pi = acos(-1.0);
inline void inc(long long &x, long long y) {
  x += y;
  if (x >= mod) x -= mod;
}
inline void dec(long long &x, long long y) {
  x -= y;
  if (x < 0) x += mod;
}
inline void chmax(long long &x, long long y) {
  if (y > x) x = y;
}
inline void mulm(long long &x, long long y) {
  x *= y;
  if (x >= mod) x -= mod;
}
long long xo(long long i) {
  if ((i & 3) == 0) return i;
  if ((i & 3) == 1) return 1;
  if ((i & 3) == 2) return i + 1;
  return 0;
}
long long p1[200005], p2[200005];
long long d[150];
int main() {
  long long n, no, m, q, i, j, k, sc, x, y, z;
  long long f = 1ll;
  string s, t;
  cin >> s >> t;
  memset(d, -1, sizeof(d));
  long long ls, lt;
  ls = s.size();
  lt = t.size();
  k = 0;
  for (i = 0; i < ls; i++) {
    if (k < lt && s[i] == t[k]) {
      d[s[i]] = k;
      p1[i] = k++;
    } else if (d[s[i]] < 0)
      f = 0;
    p1[i] = d[s[i]];
  }
  memset(d, -1, sizeof(d));
  k = lt - 1ll;
  for (long long i = ls - 1; i >= 0; i--) {
    if (k >= 0 && s[i] == t[k]) {
      d[s[i]] = k;
      p2[i] = k--;
    } else if (d[s[i]] < 0)
      f = 0;
    p2[i] = d[s[i]];
  }
  for (long long i = 0; i < ls; i++)
    if (p1[i] < p2[i]) f = 0;
  if (f)
    cout << "Yes";
  else
    cout << "No";
}
