#include<bits/stdc++.h>

using namespace std;
using ll=long long;
#define rep2(i, a, n) for(int i = (a); i < (n); i++)
#define rep(i, n) rep2(i,0,n)

void out(){cout<<endl;} template<typename Head,typename... Tail> void out(Head&& head,Tail&&... tail){cout<<head<<" ";out(forward<Tail>(tail)...);}

int main(){
  cin.tie(nullptr);ios_base::sync_with_stdio(false);
  int n,hoge=1;cin>>n;
  rep(i,n/2-1){
    hoge*=10;
    hoge++;
  }
  //out(n/2,hoge,(n%2)*7);
  cout<<hoge+(n%2)*7<<endl;
}