简单题,枚举即可
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const ll mod = 1e9 + 7;
const int N = 200005;
const int INF = 0x3f3f3f3f;
int main() {
string s;
int ans=0;
cin>>s;
for(auto i:s){
if(i>='a'&&i<='z')ans++;
}
printf("%d\n",ans);
return 0;
}