B3717 提交 CE，显示 Nothing is compiled: OUTPUT exceeds. 求助是什么意思？

代码：

#include<iostream>
using namespace std;
long long o=998244353,t,n,m,s,f[5000002]={1};
void exgcd(long long a,long long b,
	long long&x,long long&y){
	b?(exgcd(b,a%b,y,x),y-=a/b*x):(x=1,y=0);
}
long long inv(long long a){
	long long x,y;
	return exgcd(a,o,x,y),(x%o+o)%o;
}
int main(){
	scanf("%lld%lld",&t,&n);
	for(long long i=1;i<=n;i++)
		f[i]=f[i-1]*i%o;
	while(t--)
		scanf("%lld%lld",&n,&m),
		s^=f[n]*inv(f[m])%o*inv(f[n-m])%o;
	return printf("%lld",s),0;
}