#include <bits/stdc++.h>
int main() {
  char a, b, c, d, i, j, k, l;
  int ans;
  scanf("%c%c%c%c", &a, &b, &c, &d);
  d++;
  for (i = a; i <= 57; i++) {
    for (j = b; j <= 57; j++) {
      for (k = c; k <= 57; k++) {
        for (l = d; l <= 57; l++) {
          if (l != k && l != j && l != i)
            if (k != j && k != i)
              if (j != i) goto P;
        }
        d = '0';
      }
      c = '0';
    }
    b = '0';
  }
P:
  printf("%c%c%c%c", i, j, k, l);
  return 0;
}
