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

int GetInt(){
    int i;
    unsigned char c[2] = {30,30};
    int symbol = 0;
    unsigned short int err_f = 0;

    printf("Enter: ");
    scanf("%s", &c);

    for (i=0; i<2; i++){
        if(0x30 <= c[i] && c[i] <= 0x39){
            symbol *= 10;
            symbol += (c[i] - 0x30);
        } else {
            err_f = 1;
        }
    }

    if (err_f)
        return(GetInt());
    return(symbol);
}

int main()
{
    int k = GetInt();
    printf("%d", k);
    return 0;
}