输入输出

int getint()  
{  
    int t = 0;  
    char c = getchar();  
    while (c < '0' || c > '9') c = getchar();  
    while (c >= '0' && c <= '9')   
    {  
        t = t * 10 + c - '0';  
        c = getchar();  
    }  
    return t;  
}  

void Out(int a)  
{  
    if(a < 0)  
    {  
        putchar('-');  
        a = -a;  
    }  
    if(a >= 10)Out(a / 10);  
    putchar(a % 10 + '0');  
}