#include <stdio.h>

int main()
{
    int age;
    char buf[50];

    printf("How old are you?\n");
    fgets(buf, 50, stdin);
    if (sscanf(buf, "%d", &age) == 1)
	printf("Big deal, I'm %d\n", age + 3);
    else
	printf("That is not a valid age.\n");

    return 0;
}