#include <cstdio>
#include <string.h>

int _len(char* tab){
	int j = 0;
	while(tab[j] != '\0'){
		j++;
	}
	return j;
}

int ones(char* tab, int len){
	int j = 0;
	while(tab[j] == '1' && j < len){
		j++;
	}
	return j;
}

char myor(char a, char b){
	if(a == '1' || b == '1')
		return '1';
	return '0';
}

void shift(char* s1, char* s, int len, int k){
	for(int i = len - k - 1;; --i){
		if(i < 0)
			break;
		s1[i + k] = myor(s[i], s[i + k]);
	}
	for(int j = 0; j < k; ++j){
		s1[j] = s[j];
	}
}

int f(int iter, int low, int mini, int len, char* s){
	if (mini < iter){
		return mini;
	}
	int up = ones(s, len);
	if (up == len){
		return iter;
	}
	//printf("%d", up);
	for (int i = low; i < up + 1; ++i){
		char s1[40];
		shift(s1, s, len, i);
		//printf("\n%s\n", s1);
		int tmp = f(iter + 1, i, mini, len, s1);
		if (tmp < mini){
			mini = tmp;
		}
	}
	return mini;
	
}

int main(){
	char inp[40];
	scanf("%s", inp);
	int len = _len(inp);
	if (inp[0] == '0'){
		printf("%d", -1);
		return 0;
	}
	printf("%d\n", f(0, 1, 7, len, inp));
	//printf("%d", res);
	return 0;
}

/*
int main(){
	char inp[40];
	scanf("%s", inp);
	int len = _len(inp);
	int k=0, res=0;
	if (inp[0] == '0'){
		// printf("%d", -1);
		return 0;
	}
	for(;;){
		k = ones(inp, len);
		// printf("%s", inp);
		if(k == len)
			break;
		++res;
		// printf(" %d \n", k);
		for(int i = len - k - 1;; --i){
			if(i < 0)
				break;
			inp[i + k] = myor(inp[i], inp[i + k]);
		}
	}
	printf("%d", res);
	return 0;
}*/