#include <bits/stdc++.h>
using namespace std;
int dp[1010][1010], l1, l2;
string s1, s2;
int main() {
  cin >> s1 >> s2;
  l1 = s1.length();
  l2 = s2.length();
  for (int i = 0; i <= l2; i++) dp[0][i] = i;
  for (int i = 0; i <= l1; i++) dp[i][0] = i;
  for (int i = 1; i <= l1; i++)
    for (int j = 1; j <= l2; j++)
      dp[i][j] = min((s1[i - 1] != s2[j - 1]) + dp[i - 1][j - 1],
                     1 + min(dp[i][j - 1], dp[i - 1][j]));
  cout << dp[l1][l2] << endl;
  while (l1 > 0 || l2 > 0) {
    if (dp[l1][l2] == 1 + dp[l1][l2 - 1] && l2 != 0)
      cout << "INSERT " << l1 + 1 << " " << s2[--l2] << endl;
    else if (dp[l1][l2] == 1 + dp[l1 - 1][l2] && l1 != 0)
      cout << "DELETE " << l1-- << endl;
    else if (s1[--l1] != s2[--l2])
      cout << "REPLACE " << l1 + 1 << " " << s2[l2] << endl;
  }
  return 0;
}
