#include<bits/stdc++.h>
#define ll long long
#define db double
#define str string
#define fi first
#define se second
#define mod 47
#define inf INFINITY
#define maxn 100000
#define si size()
using namespace std;
int main()
{
    ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
    //freopen(".inp","r",stdin);
    //freopen(".out","w",stdout);
    str a;
    cin>>a;
    ll s=0;
    for(char i:a)
    {
        s+=(tolower(i)=='a');
    }
    cout<<s;
}