发帖.感想：QwQ

#include<bits/stdc++.h>
using namespace std;
int n,p,num,i,j,k; 
vector<vector<int> > v;
int main(){
	cin>>n>>p;
    while(p--){
    	cin>>num;
    	if(num==1){
    		cin>>i>>j>>k;
    		v[i][j]=k;
		}else{
			cin>>i>>j;
			cout<<v[i][j]<<endl;
		}
	}
	return 0;
}