#include <stdio.h>
#include <string.h>

int main(void) {
	int c = 0;
	int w = 0;
	int i;
	int j;
	int l;
	char s[100001];
	scanf("%s",s);
	l = strlen(s);
	j = l / 2;
	while (s[j] == 'w') {
		j = j / 2;
	}
	for (i = j;i < l;i++) {
		if(s[i] == 'w')  {
			c = i;
			w = l - c;
			break;
		}
	}
	if (c-1 > w) {
		printf("%d\n",w);
	}
	else {
		printf("%d\n",c-1);
	}
	return 0;
}