#include <stdio.h>

int main(){
  char in[101];
  int a, p = 0, i = 0, ans = 101;
  scanf("%s", in);

  while(in[i] != '\0'){
    switch(p){
    case 0:
      if(in[i] == 'c'){
        a = 1;
        p = 1;
      }
      break;
    case 1:
      a++;
      if(in[i] == 'c') a = 0;
      if(in[i] == 'w') p = 2;
      break;
    case 2:
      a++;
      if(in[i] == 'w'){
        if(a < ans) ans = a;
        p = 0;
      }
    }
    i++;
  }
  if(ans == 101) ans = -1;
  printf("%d\n", ans);
  return 0;
}