import std.stdio, std.algorithm, std.array, std.string, std.math, std.conv;

void main() {
  char[] s = readln.chomp.to!(char[]);
  char now1 = s[0], now2 = s[$ - 1];
  ulong cur1, cur2;
  foreach (i, c; s) {
    if (now1 != c) {
      cur1 = i;
      break;
    }
  }
  foreach_reverse (i, c; s) {
    if (now2 != c) {
      cur2 = i;
      break;
    }
  }

  writeln(max(s.length - cur1, cur2 + 1));
}
