#include <stdio.h>
char in[101];
int count(int i){
  int p = 1, a = 1;
  while(in[i] != '\0'){
    a++;
    if(in[i]=='w')
      if(p==1) p++;
      else return a;
    i++;
  }
  return 101;
}

int main(){
  int ans = 101, i = 0, c;
  scanf("%s", in);

  while(in[i] != '\0'){
    if(in[i] == 'c'){
      c = count(i + 1);
      if(c < ans) ans = c;
    }
    i++;
  }  
  if(ans == 101) ans = -1;
  printf("%d\n", ans);
  return 0;
}