读入优化模板

inline int read(){
    int s = 0,f = 1;
    char ch;
    ch = getchar();
    while(!isdigit(ch)){
        if(ch == '-') f = - 1;
        ch = getcahr();
    }
    while(isdigit(ch)){
        s = s*10 + ch - '0';
        ch = getcahr();
    }
    return s*f;
}