#include <iostream>
#include <vector>
using namespace std;

int vectorSumm(vector<bool> v) {
	int summ=0;
	for (int i=0; i<v.size(); i++) {
		if (v[i]) summ++;
	}
	return summ;
}

bool tryC(int *st, vector<bool> corrals){
	for(int j = 0; j < 6; ++j){
		if(st[j] == 0)
			break;
		
		for(size_t i = corrals.size()-1; i >= st[j]; --i){
			if(corrals[i - st[j]]){
				corrals[i] = true;
			} 
		}
	}
	
	return (vectorSumm(corrals) == (int)corrals.size());
	
}

int main() {
	vector<bool> corrals;
	string inpt;
	cin >> inpt;
	int arr[5];
	
	for (int i=0; i<inpt.length(); i++) {
		corrals.push_back(((int)(inpt[i]-'0'))==1);
	}
	
	
	if (!corrals[0]) {
		cout << -1;
		return 0;
	}
	int minr = 6, r = 0;
	for(int i1 = 0; i1 < 20; ++i1){
		arr[0] = i1;
		for(int i2 = 0; i2 < 20; ++i2){
			arr[1] = i2;
			for(int i3 = 0; i3 < 20; ++i3){
				arr[2] = i3;
				for(int i4 = 0; i4 < 20; ++i4){
					arr[3] = i4;
					for(int i5 = 0; i5 < 20; ++i5){
						arr[4] = i5;
					//	for(int i6 = 0; i6 < 20; ++i6){
						//	arr[5] = i6;
							if(tryC(arr, corrals)){
								r = 5;
								//if(i6 == 0) r--;
								if(i5 == 0) r--;
								if(i4 == 0) r--;
								if(i3 == 0) r--;
								if(i2 == 0) r--;
								if(i1 == 0) r--;
								if(r < minr)
									minr = r;
							}
						//}
					}
				}
			}
		}
	}
	finish:
	cout << minr;
	return 0;
	/*
	int best=0;
	
	while (true) {
		bool all = false;
		int cnt=0;
		
		for(size_t i = 0; i < corrals.size(); ++i){
			if(corrals[i])
			cnt ++;
			else break;
		}
		if(cnt == (int)corrals.size())
			break;
			
		++best;
		for(size_t i = corrals.size()-1; i >= cnt; --i){
			if(corrals[i - cnt]){
				corrals[i] = true;
			} 
		}
	}
	* */
	/*
	vector<bool> corralsCurr;
	vector<bool> corralsCurrCurr;
	
	int vectorSumPrev, vectorSumNow;
	vectorSumPrev = vectorSumNow = 0;
	
	int iterations;
	
	for (int K=1; K<corrals.size(); K++) {
		corralsCurr=corrals;
		iterations=0;
		vectorSumPrev=245724;
		vectorSumNow=14512345;
		while (vectorSumPrev!=vectorSumNow && vectorSumNow != corrals.size()) {
			iterations++;
			vectorSumPrev = vectorSumm(corralsCurr);
			corralsCurrCurr=corralsCurr;
			for (int j = 0; j<corralsCurr.size(); j++) {
				if (corralsCurr[j]) {
					if (j+K<corralsCurr.size()) {
						corralsCurrCurr[j+K]=true;
					}
 				}
			}
			corralsCurr=corralsCurrCurr;
			vectorSumNow= vectorSumm(corralsCurr);
		}
		if (vectorSumm(corralsCurr) == corrals.size()) {
			if (iterations<best) {
				best = iterations;
			}
		}
	}
	*/
	
	//cout << best;
	
	return 0;
}