读入优化

int readint(){//读入优化 
    int Num;
    char ch;
    while((ch=getchar())<'0'||ch>'9');//这里有分号
    Num=ch-'0';
    while((ch=getchar())>='0'&&ch<='9'){
        Num=Num*10+ch-'0';
    } 
    return Num;
}