#include<stdio.h>
#include<string.h>
#include<algorithm>
main(){
    char S[100001];
    scanf("%s",S);
    int x;
    for(int i = 0;i < strlen(S);i++){
        if(S[i] == 'w'){
            x = i;
            break;
        }
    }
    printf("%d\n",std::min(x-1,(int)strlen(S)-x));
}