#include <iostream>

using namespace std;

void numar(int n, int c1, int c2, int &x)
{
    x=0;
    while(n)
    {
        if(n%10>=c1 && n%10<=c2)
            x=x+n%10;
        n=n/10;
    }
}
int main()
{
    int x;
    numar(123, 2, 7, x);
    cout<<x;
}