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

void print_numbers(char *input);

int main(int argc, char *argv[])
{
    if (argc == 1)
    {
        char buf[LINE_MAX+1];
        while (fgets(buf, LINE_MAX, stdin))
            print_numbers(buf);
    }
    else
    {
        for (int k = 1; k < argc; k++)
        {
            char *input = argv[k];
            print_numbers(input);
        }
    }

    return 0;
}

void print_numbers(char *input)
{
    int len = strlen(input);
    char *buf = malloc((len * sizeof(char)) + 1);
    if (buf)
    {
        int j = 0;
        for (int i = 0; i < len; i++)
        {
            char c = input[i];
            if (c >= 48 && c <= 57)
                buf[j++] = c;
        }
        buf[j] = '\0';

        printf("%s", buf);
        free(buf);
    }
}