C语言训练-邮票组合问题*简洁版

#include<stdio.h>

int main(void)
{
    int three,four;
    int i;
    int num = 0;
    for(three = 0; three <= 4; three++)
    {
        for (four = 0; four <= 3; four++)
        num++;
    }
         printf("%d\n",num-1);
    return 0;
}