#include <stdio.h>
#include <stdlib.h>

int leerDigito(){
    char digito;
    scanf("%c",&digito);
    switch(digito) {
    case '0': return 0;
    break;
    case '1' : return 1;
    break;
    case '2': return 2;
    break;
    case '3': return 3;
    break;
    case '4': return 4;
    break;
    case '5': return 5;
    break;
    case '6': return 6;
    break;
    case '7': return 7;
    break;
    case '8': return 8;
    break;
    case '9': return 9;
    break;
    case 'A': return 10;
    break;
    case 'B': return 11;
    break;
    case 'C': return 12;
    break;
    case 'D': return 13;
    break;
    case 'E': return 14;
    break;
    case 'F': return 15;
    break;
    default : return -1;
}

}
int sumatoria(int *E){
    int dig=leerDigito();
    int suma;
    if(dig==-1){
        suma= 0;
    }else{
        suma=sumatoria(&E);
        suma+=dig*(E)+sumatoria(&E);
        &E=&E*16;


    }
}
int sumatoriaAux(){
    int E=1;
    sumatoria(&E);
}

int main()
{
    printf("%d",leerDigito());
return 0;
}