#include <bits/stdc++.h>
using namespace std;
const int MAXN = 1010;
char s[MAXN], t[MAXN];
int m, n;
int dp[MAXN][MAXN];
int op[MAXN][MAXN];
const char *name[] = {"", "INSERT", "DELETE", "REPLACE"};
void print(int x, int y) {
  if (!x && !y) return;
  if (op[x][y] == 0) print(x - 1, y - 1);
  if (op[x][y] == 1) print(x, y - 1);
  if (op[x][y] == 2) print(x - 1, y);
  if (op[x][y] == 3) print(x - 1, y - 1);
  if (op[x][y] == 1) printf("%s %d %c\n", name[1], y, t[y]);
  if (op[x][y] == 2) printf("%s %d\n", name[2], y + 1);
  if (op[x][y] == 3) printf("%s %d %c\n", name[3], y, t[y]);
}
int main() {
  m = strlen(gets(s + 1));
  n = strlen(gets(t + 1));
  for (int i = 1; i <= m; ++i) {
    dp[i][0] = i;
    op[i][0] = 2;
  }
  for (int i = 1; i <= n; ++i) {
    dp[0][i] = i;
    op[0][i] = 1;
  }
  for (int i = 1; i <= m; ++i)
    for (int j = 1; j <= n; ++j) {
      if (s[i] == t[j]) {
        dp[i][j] = dp[i - 1][j - 1];
        op[i][j] = 0;
      } else {
        dp[i][j] = 1 + dp[i][j - 1];
        op[i][j] = 1;
      }
      if (1 + dp[i - 1][j] < dp[i][j]) {
        dp[i][j] = 1 + dp[i - 1][j];
        op[i][j] = 2;
      }
      if (1 + dp[i - 1][j - 1] < dp[i][j]) {
        dp[i][j] = 1 + dp[i - 1][j - 1];
        op[i][j] = 3;
      }
    }
  printf("%d\n", dp[m][n]);
  print(m, n);
}
