题解

#include<iostream>
using namespace std;
int main(){
    string s;
    getline(cin,s);
    int sum=0;
    for (int i=0;i<s.size();i++){
        if(s[i]>='A'&&s[i]<='Z'){
            sum++;
        }else if(s[i]>='a'&&s[i]<'z'){
            sum++;
        }else if(s[i]>='0'&&s[i]<='9'){
            sum++;
        } 
    }
    cout<<sum;
    return 0;
}