#include <iostream>
#include <vector>
using namespace std;
typedef vector<int> lll;
typedef long long ll;
const int base = 1000*1000*1000;
const long long e=10, k=1;
lll readlong(){lll a;string s;cin>>s;
    for(int i=s.size()-1;i>=0;i--)a.push_back(s[i]-'0');
    return a;}
void writelong(lll a){
    for(int i=a.size()-1;i>=0;i--)cout<<a[i];}
bool GTlong(lll a, lll b){
    if(a.size()>b.size())return true;
    if(a.size()<b.size())return false;
    for(int i=a.size()-1;i>=0;i--){
        if(a[i]>b[i])return true;
        if(a[i]<b[i])return false;}
return false;}
lll operator +(lll a,lll b){
	lll c;int i,r=0;
	for(i=0;i<a.size()||i<b.size();i++){
		if(i<a.size())r+=a[i];
		if(i<b.size())r+=b[i];
		c.push_back(r%e); r/=e;}
		if(r)c.push_back(r);
	return c;}
lll operator -(lll a,lll b){
	lll c;int i,r=0;
	for(i=0;i<a.size();i++){
		r+=a[i];
		if(i<b.size())r-=b[i];
		if(r<0){c.push_back(r+10);r=-1;}
		else{c.push_back(r%10);r=0;}}
		while(c.size()>1&&c.back()==0)c.pop_back();
		return c;}
lll operator *(lll a,ll b){
	lll c;int i;ll r=0;
	if(b==0){c.push_back(0);return c;}
	for(i=0;i<a.size();++i){
	    r+=a[i]*b;
		c.push_back(r%e);r/=e;}
		while(r){c.push_back(r%e);r/=e;}
	return c;}
lll operator *(lll a,lll b){
	lll c(1,0),d;int i,j;
	if(a==d||b==d)return d;
	if(b.size()>a.size())swap(a,b);
	for(i=0;i<b.size();i++){
	    c=a*b[i];
		for(j=0;j<i;j++)c.insert(c.begin(),0);
		d=d+c;}
	return d;}
lll operator /(lll a,ll b){
	lll c;int i;ll r=0,t;
	for(i=a.size()-1;i>=0;i--){
	    r=r*10+a[i];t=r/b;
		c.insert(c.begin(),t);r-=t*b;}
	while(c.size()>1&&c[c.size()-1]==0)
		c.resize(c.size()-1);
	return c;}
lll operator %(lll a,ll b){
	lll c;int i;lll r={0},t;
	for(i=a.size()-1;i>=0;i--){lll d={a[i]};
	    r=r*10+d;t=r/b;r=r-t*b;}
	return r;}
bool operator ==(lll a, lll b){
    if(a.size()!=b.size())return false;
    for(int i=0;i<a.size();i++){
        if(a[i]!=b[i])return false;}
    return true;}
bool operator>(lll a, lll b){
    if(a.size()>b.size())return true;
    if(a.size()<b.size())return false;
    for(int i=a.size()-1;i>=0;i--){
        if(a[i]>b[i])return true;
        if(a[i]<b[i])return false;}
return false;}
int main(){
    lll a,b={0},c={4},min={1}; ll n,m,i,j,k; vector<lll>d;
    for(i=0;i<=100;i++)min=min*10;
    a=readlong();
    if(a==c)cout<<7;
    else{
    for(i=0;i<a.size();i++){
    	if(a[i]==4){
    	for(j=0;j<=9;j++){
	        a[i]=j;
      	    if(a%7==b&&a[a.size()-1]!=0){d.push_back(a);break;}}
	    a[i]=4;}}
    for(i=0;i<d.size();i++)if(min>d[i])min=d[i];
    writelong(min);}
return 0;}