#include <bits/stdc++.h>
using namespace std;
int const maxn = 1010;
int long dp[maxn][maxn];
string a, b;
void print(int long n, int long m) {
  if (n == 0 && m == 0) {
    return;
  }
  if (a[n] == b[m] && n != 0 && m != 0) {
    print(n - 1, m - 1);
  } else if (dp[n][m] == dp[n][m - 1] + 1 && m != 0) {
    print(n, m - 1);
    cout << "INSERT " << m << ' ' << b[m] << endl;
  } else if (dp[n][m] == dp[n - 1][m] + 1 && n != 0) {
    print(n - 1, m);
    cout << "DELETE " << m + 1 << endl;
  } else if (dp[n][m] == dp[n - 1][m - 1] + 1 && n != 0 && m != 0) {
    print(n - 1, m - 1);
    cout << "REPLACE " << m << ' ' << b[m] << endl;
  }
}
int main() {
  int long n, m;
  cin >> a >> b;
  n = a.size();
  m = b.size();
  a = ' ' + a;
  b = ' ' + b;
  for (int i = 0; i <= n; i++) {
    dp[i][0] = i;
  }
  for (int j = 0; j <= m; j++) {
    dp[0][j] = j;
  }
  for (int i = 1; i <= n; i++) {
    for (int j = 1; j <= m; j++) {
      if (a[i] == b[j]) {
        dp[i][j] = dp[i - 1][j - 1];
      } else {
        dp[i][j] = min(dp[i - 1][j], min(dp[i][j - 1], dp[i - 1][j - 1])) + 1;
      }
    }
  }
  cout << dp[n][m] << endl;
  print(n, m);
}
