#include <iostream>
#include <string>
#include <algorithm>
using namespace std;
int main()
{
string s;
cin >> s;
int state = 0;
int start = 0;
int HOGE = 10000000;
int mini = HOGE;
for(int i = 0; i < s.size(); i++){
if(state==0){
if(s[i] == 'c'){
start = i;
state = 1;
}
} else if (state == 1){
if(s[i] == 'w'){
state = 2;
}
} else if (state ==2){
if(s[i] == 'w'){
mini = min(mini, i-start+1);
state = 0;
}
}
}
if(mini == HOGE){
cout << -1 << endl;
} else {
cout << mini << endl;
}
return 0;
}