#include<iostream>
#include<vector>
using namespace std;
 
int main(){
  int N, M;
  cin >> N >> M;
  vector<int> s(M),c(M);
  for (int i = 0; i < M; i++){
    cin >> s[i] >> c[i];
  }
  vector<int> num(N,0);
  
  for (int i = 0; i < M; i++){
    num[s[i]-1] = c[i];
  }
  bool notzero = false;
  for (int i = 0; i < N; i++){
    if (num[i] != 0) notzero = true;
    if(notezero) cout << num[i];
  }
}