#include <iostream>
#include <string>
#include <regex>
#include <algorithm>

int main() {
    std::string s;	
    std::cin >> s;	
    std::regex r("(?=([^*][*]*[^*]))");
    
    int best = s.size();
    for (auto i = std::sregex_iterator(s.begin(), s.end(), r); i != std::sregex_iterator(); ++i) {
        int pos = i->position(1);
        int len = i->length(1); 
        if (s[pos] != s[pos + len -1]) {
        	best = std::min(len-2, best);
        }
    }	
    std::cout << best;
    return 0;
}