ЗАДАЧА №322 Слово

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

int main()
{
	int a = 1, b = 2, i = 0;
	string s ;
	cin >> s;
	while(a <= s.size()) {
		cout << s[a - 1];
		i = a;
		a = b;
		b = i + b;
	}
	return 0;
}