#include <stdio.h>
int main()
{
int longest = 1;
char line[1024] = {0};
gets(line + 1); /* line[0] as sentinel */
char *lo, *hi;
for (char *p = line + 1; *p; ++p) {
for (lo = p; *lo == *p; --lo);
for (hi = p; *hi == *p; ++hi);
for (; *lo == *hi && *lo && *hi; --lo, ++hi);
if (hi - lo - 1 > longest) longest = hi - lo - 1;
}
printf("%d\n", longest);
return 0;
}