rt

传统：

inline ll read(){   
    ll num=0,f=1;  
    char chr=getchar();
    while(chr<'0'||chr>'9'){   
        if(chr=='-') f=-1;
        chr=getchar();
    }
    while(chr>='0'&&chr<='9'){    
        num=num*10+chr-'0';   
        chr=getchar();
    } 
    return num*f;
}