#include <bits/stdc++.h>
using namespace std;
const int mod = 1000 * 1000 * 1000 + 7;
const int maxn = 1000 + 10;
const int inf = 10000000;
string s, t;
int dp[maxn][maxn], par[maxn][maxn];
int f(int poss, int post) {
  if (dp[poss][post] != -1) return dp[poss][post];
  if (poss <= 0 && post > 0) {
    par[poss][post] = 1;
    return dp[poss][post] = f(poss, post - 1) + 1;
  }
  if (poss == 0 && post == 0) return 0;
  if (poss > 0 && post == 0) {
    par[poss][post] = 2;
    return dp[poss][post] = f(poss - 1, post) + 1;
  }
  if (s[poss - 1] == t[post - 1]) {
    par[poss][post] = 4;
    return dp[poss][post] = f(poss - 1, post - 1);
  }
  int ins = f(poss, post - 1) + 1;
  int del = f(poss - 1, post) + 1;
  int rep = f(poss - 1, post - 1) + 1;
  if (ins <= del && ins <= rep) {
    par[poss][post] = 1;
    return dp[poss][post] = ins;
  }
  if (del <= ins && del <= rep) {
    par[poss][post] = 2;
    return dp[poss][post] = del;
  }
  par[poss][post] = 3;
  return dp[poss][post] = rep;
}
int main() {
  for (int i = 0; i < maxn; i++)
    for (int j = 0; j < maxn; j++) dp[i][j] = -1;
  cin >> s >> t;
  cout << f(s.size(), t.size()) << endl;
  int x = s.size(), y = t.size();
  while (x > 0 || y > 0) {
    if (par[x][y] == 1) {
      cout << "INSERT " << x + 1 << ' ' << t[y - 1] << endl;
      y--;
    } else if (par[x][y] == 2) {
      cout << "DELETE " << x << endl;
      x--;
    } else if (par[x][y] == 3) {
      cout << "REPLACE " << x << ' ' << t[y - 1] << endl;
      x--;
      y--;
    } else
      x--, y--;
  }
  return 0;
}
