60pts MLE求调

#include<bits/stdc++.h>
using namespace std;
int a[10000001],b[10000001],n,k,x,y; 
long long s1=0,s2=0;
int main(){
	cin>>n>>k;
	for(int i=1;i<=k;i++){
		cin>>x>>y;
		if(a[x]==0){
			s1++;
			a[x]=1;
		}
		if(b[y]==0){
			s2++;
			b[y]=1;
		}
	}
	cout<<s1*n+s2*n-s1*s2;
}