#include<stdio.h>

int main(int argc, char const *argv[]) {
    /* code */
    char str[256];
    int wp = 0;
    int flag = 0, cnt = 0;

    while(fscanf(stdin, "%c", &str[wp++]) != EOF){
        if(str[wp - 1] == 'c'){
            while(fscanf(stdin, "%c", &str[wp++]) != EOF){
                cnt++;
                if(str[wp - 1] == 'w'){
                    while(fscanf(stdin, "%c", &str[wp++]) != EOF){
                        cnt++;
                        if(str[wp - 1] == 'w'){
                            cnt++;
                            flag = 1;
                            break;
                        }
                    }
                    break;
                }
            }
            break;
        }
    }

    if(flag == 1){
        fprintf(stdout, "%d\n", cnt);
    }else{
        fprintf(stdout, "-1\n");
    }
    return 0;
}