c++ why my second if statment not working [on hold]

when i write my code its all good until the second time i use the if statment it doesent even allow for you to put yes or no its just reads the first if (great,you should....)can anybody help me im still a beginner and new to c++ and explaining why it work or doesent would mean a lot so i dont make the same mistake twice

#include <iostream>
#include <string>
using namespace std;
int main()
{
    cout << "hello and welcome to c++" << endl
         << endl;

    cout << "whats your name?" << endl;
    string name;
    cin >> name;
    cout << endl;

    cout << "hello " << name << ",whats your last name?" << endl
         << endl;
    string last;
    cin >> last;
    cout << endl;

    cout << " " << name << " " << last << " thats a pretty name" << endl
         << endl;
    cout << "how old are you?" << endl;
    int age;
    cin >> age;
    cout << endl;

    {
        if (age < 18)
            cout << "wow youre so young" << endl;

        else if (age >= 18 && age < 30)
            cout << "young adult eh" << endl;

        else if (age > 30)
            cout << "were always young at heart" << endl;

        else
            cout << "dont wanna say?ah to bad" << endl;
    }

    cout << "did you take a shower today?" << endl;
    string input;
    {
        int yes, no;
        if (input.compare("Yes"))
            cout << "great,you should shower everyday" << endl;

        else if (input.compare("No"))
            cout << "ou really?You know you should shower everyday" << endl;

        else
            cout << "weird question right hahah" << endl;
    }
    return 0;
}