Language: C++

#include<bits/stdc++.h> namespace ZDY{     #pragma GCC optimize(3)     #define il __inline__ __attribute__ ((always_inline))     #define rg register     #define ll long long     #define ull unsigned long long     #define db double     #define sht short     #define MB template <class T>il     #define Fur(i,x,y) for(int i=x;i<=y;i++)     #define Fdr(i,x,y) for(int i=x;i>=y;i--)     #define fl(i,x) for(int i=head[x],to;to=e[i].to,i;i=e[i].nxt)     #define clr(x,y) memset(x,y,sizeof(x))     #define cpy(x,y) memcpy(x,y,sizeof(x))     #define fin(s) freopen(s".in","r",stdin)     #define fout(s) freopen(s".out","w",stdout)     #define fcin ios::sync_with_stdio(false)     #define l2(n) ((int)(log2(n)))     #define inf 0x3f3f3f3f     MB T ABS(T x){return x>0?x:-x;}     MB T MAX(T x,T y){return x>y?x:y;}     MB T MIN(T x,T y){return x<y?x:y;}     MB T GCD(T x,T y){return y?GCD(y,x%y):x;}     MB void SWAP(T &x,T &y){T t=x;x=y;y=t;} }using namespace ZDY;using namespace std; namespace IO{const char* ln="\n";const int str=1<<20;struct IN{char buf[str],*s,*t;bool _;IN():s(buf),t(buf),_(0){}il char gc(){return s==t&&((t=(s=buf)+fread(buf,1,str,stdin))==s)?EOF:(*s++);}IN&operator>>(char&ch){if(_)return *this;char c;while((c=gc())!=EOF&&isspace(c));if(c==EOF)_=1;else ch=c;return *this;}IN& operator>>(char* ch){clr(ch,0);if(_)return *this;char c;while((c=gc())!=EOF&&isspace(c));if(c==EOF)return _=1,*this;*ch=c;ch++;while((c=gc())!=EOF&&!isspace(c))*ch=c,ch++;if(c==EOF)_=1;return *this;}IN& operator>>(string& ch){if(_)return *this;char c;while((c=gc())!=EOF&&isspace(c));if(c==EOF)return _=1,*this;ch+=c;while((c=gc())!=EOF&&!isspace(c))ch+=c;if(c==EOF)_=1;return *this;}template<typename T>IN&operator>>(T&x){if(_)return *this;char c=gc();bool ff=0;while(c!=EOF&&(c<'0'||c>'9'))ff^=(c=='-'),c=gc();if(c==EOF){_=1;return *this;}x=0;while(c!=EOF&&'0'<=c&&c<='9')x=(x<<3)+(x<<1)+c-48,c=gc();if(c==EOF)_=1;if(ff)x=-x;return *this;}}in;struct OUT{char buf[str],*s,*t;OUT():s(buf),t(buf+str){}~OUT(){fwrite(buf,1,s-buf,stdout);}void pt(char c){(s==t)?(fwrite(s=buf,1,str,stdout),*s++=c):(*s++=c);}OUT&operator<<(const char*s){while(*s)pt(*s++);return *this;}OUT&operator<<(char*s){while(*s)pt(*s++);return *this;}OUT&operator<<(string s){for(int i=0;s[i];i++)pt(s[i]);return *this;}template<typename T>OUT&operator<<(T x){if(!x)return pt('0'),*this;if(x<0)pt('-'),x=-x;char a[30],t=0;while(x)a[t++]=x%10,x/=10;while(t--)pt(a[t]+'0');return *this;}}out;}using namespace IO; #define N 111 int n; int main(){     int a,b;     in>>a>>b;     out<<MAX(0,a-2*b); }



Compiler output:
a.cc:1:25: warning: extra tokens at end of #include directive
    1 | #include<bits/stdc++.h> namespace ZDY{     #pragma GCC optimize(3)     #define il __inline__ __attribute__ ((always_inline))     #define rg register     #define ll long long     #define ull unsigned long long     #define db double     #define sht short     #define MB template <class T>il     #define Fur(i,x,y) for(int i=x;i<=y;i++)     #define Fdr(i,x,y) for(int i=x;i>=y;i--)     #define fl(i,x) for(int i=head[x],to;to=e[i].to,i;i=e[i].nxt)     #define clr(x,y) memset(x,y,sizeof(x))     #define cpy(x,y) memcpy(x,y,sizeof(x))     #define fin(s) freopen(s".in","r",stdin)     #define fout(s) freopen(s".out","w",stdout)     #define fcin ios::sync_with_stdio(false)     #define l2(n) ((int)(log2(n)))     #define inf 0x3f3f3f3f     MB T ABS(T x){return x>0?x:-x;}     MB T MAX(T x,T y){return x>y?x:y;}     MB T MIN(T x,T y){return x<y?x:y;}     MB T GCD(T x,T y){return y?GCD(y,x%y):x;}     MB void SWAP(T &x,T &y){T t=x;x=y;y=t;} }using namespace ZDY;using namespace std; namespace IO{const char* ln="\n";const int str=1<<20;struct IN{char buf[str],*s,*t;bool _;IN():s(buf),t(buf),_(0){}il char gc(){return s==t&&((t=(s=buf)+fread(buf,1,str,stdin))==s)?EOF:(*s++);}IN&operator>>(char&ch){if(_)return *this;char c;while((c=gc())!=EOF&&isspace(c));if(c==EOF)_=1;else ch=c;return *this;}IN& operator>>(char* ch){clr(ch,0);if(_)return *this;char c;while((c=gc())!=EOF&&isspace(c));if(c==EOF)return _=1,*this;*ch=c;ch++;while((c=gc())!=EOF&&!isspace(c))*ch=c,ch++;if(c==EOF)_=1;return *this;}IN& operator>>(string& ch){if(_)return *this;char c;while((c=gc())!=EOF&&isspace(c));if(c==EOF)return _=1,*this;ch+=c;while((c=gc())!=EOF&&!isspace(c))ch+=c;if(c==EOF)_=1;return *this;}template<typename T>IN&operator>>(T&x){if(_)return *this;char c=gc();bool ff=0;while(c!=EOF&&(c<'0'||c>'9'))ff^=(c=='-'),c=gc();if(c==EOF){_=1;return *this;}x=0;while(c!=EOF&&'0'<=c&&c<='9')x=(x<<3)+(x<<1)+c-48,c=gc();if(c==EOF)_=1;if(ff)x=-x;return *this;}}in;struct OUT{char buf[str],*s,*t;OUT():s(buf),t(buf+str){}~OUT(){fwrite(buf,1,s-buf,stdout);}void pt(char c){(s==t)?(fwrite(s=buf,1,str,stdout),*s++=c):(*s++=c);}OUT&operator<<(const char*s){while(*s)pt(*s++);return *this;}OUT&operator<<(char*s){while(*s)pt(*s++);return *this;}OUT&operator<<(string s){for(int i=0;s[i];i++)pt(s[i]);return *this;}template<typename T>OUT&operator<<(T x){if(!x)return pt('0'),*this;if(x<0)pt('-'),x=-x;char a[30],t=0;while(x)a[t++]=x%10,x/=10;while(t--)pt(a[t]+'0');return *this;}}out;}using namespace IO; #define N 111 int n; int main(){     int a,b;     in>>a>>b;     out<<MAX(0,a-2*b); }
      |                         ^~~~~~~~~
/usr/bin/ld: /usr/lib/gcc/x86_64-linux-gnu/14/../../../x86_64-linux-gnu/Scrt1.o: in function `_start':
(.text+0x17): undefined reference to `main'
collect2: error: ld returned 1 exit status