#include <iostream>
#include <limits>
#include <cstdlib>

using namespace std;

main()
{
    int t;
    string s;
    char *end;

    while (1) {
        cout << "Enter a number: ";
        cin >> s;
        cin.ignore(numeric_limits<streamsize>::max(),'\n');
        t = strtol(s.c_str(), &end, 10);

        if (t>26 || t<0 || (*end!=0) || s.empty()) {
            cout << "Please enter an integer between 0 and 26.\n";
            continue;
        }

        cout << "You entered " << t << "\n";
    }
}