#define _CRT_SECURE_NO_WARNINGS
#include <bits/stdc++.h>
using namespace std;
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr) ;
string s;
cin >> s;
int count = 0;
while (!s.empty() && s[0] != 'a') {
s.erase(0, 1);
count++;
}
cout << s.length();
return 0;
}
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