why the NZEC error

#include<stdio.h>
void main()
{
int N,i;
int x1,x2,lead1=0,lead2=0,p1=0,p2=0,maxLead=0,aLead=0,currentMaxLead=0,isFirst=0,isSecond=0;
scanf("%d",&N);

for(i=0;i<N;i++)
{
scanf("%d%d",&x1,&x2);
lead1+=x1;
lead2+=x2;
if(lead1>lead2)
{
 
 p1++;
 aLead=x1-x2;
 if(maxLead<aLead){
	maxLead=aLead;
	if(currentMaxLead<maxLead){
	 currentMaxLead=maxLead;
	 isFirst=1;
	 isSecond=0;
	 }
 }
 
 
}
else
{
 
 p2++;
 aLead=x2-x1;
 if(maxLead<aLead){
	maxLead=aLead;
	if(currentMaxLead<maxLead){
	 currentMaxLead=maxLead;
	 isFirst=0;
	 isSecond=1;
 
	 }
 }
}
 
}
 
 
 
if(isFirst==1)
 
{
printf("1 %d",maxLead);
}
else
{
printf("2 %d",maxLead);
}
 
return 0;
}

what’s wrong with my program?
I keep getting NZEC error

Replace “void main” by “int main”. You do “return 0” as the end of your code, but you declare main as returning void…

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